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Abstracts Brochure - 2nd International Particle Accelerator Conference

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IPAC’11<br />

Special Poster Session for Young Scientists and<br />

EPS-AG Prize d) Candidates<br />

Sunday, 4 September<br />

(Setting up from 14:00, Prize d) and Student Poster Prizes judging from 15:00 to 18:00)<br />

Foyer Auditorium Level 0, Kursaal, San Sebastian<br />

Classification Main Classification Panels Page<br />

Classification 1 Circular <strong>Accelerator</strong>s 1-9 1<br />

Classification 2 Synchrotron Light Sources and FELs 10-23 3<br />

Classification 3 Linear Colliders, Lepton <strong>Accelerator</strong>s and New Acc. Techniques 24-34 7<br />

Classification 4 Hadron <strong>Accelerator</strong>s 35-46 11<br />

Classification 5 Beam Dynamics and Electromagnetic Fields 47-74 15<br />

Classification 6 Beam Instrumentation and Feedback 75-95 23<br />

Classification 7 <strong>Accelerator</strong> Technology 96-123 29<br />

Classification 8 Applications of <strong>Accelerator</strong>s 124-127 37<br />

Layout of the Student Poster Session<br />

Foyer Auditorium Level 0, Kursaal, San Sebastian


Poster Panel 1<br />

ID: 4068 - TUPZ028<br />

Beam Based Optimization of the Squeeze at the<br />

LHC, Xavier Buffat (EPFL, Lausanne),<br />

Mike Lamont, Stefano Redaelli, Jorg Wenninger<br />

(CERN, Geneva) - The betatron squeeze is a critical<br />

operational phase for the LHC because it is carried<br />

out at top energy, with the maximum stored energy<br />

and with reduced aperture margins in the<br />

superconducting triplets. A stable operation with<br />

minimum beam losses must be achieved in order to<br />

ensure a safe and efficient operation. The<br />

operational experience at the LHC showed that this<br />

is possible. The operation in 2010 is reviewed. In<br />

particular, orbit, tune and chromaticity<br />

measurements are investigated and correlated to<br />

beam losses. Different optimizations are then<br />

proposed towards a more efficient and robust<br />

operation. The improvements obtained for the<br />

operation in 2011 are presented.<br />

Sub Classification: A01 Hadron Colliders<br />

Poster Panel 2<br />

ID: 3840 - TUPZ015<br />

Electron Cloud Parameterization Studies in the<br />

LHC, César Octavio Domínguez,<br />

Gianluigi Arduini, Vincent Baglin, Giuseppe<br />

Bregliozzi, José Miguel Jimenez, Elias Métral,<br />

Giovanni Rumolo, Daniel Schulte, Frank<br />

Zimmermann (CERN, Geneva) - During LHC beam<br />

commissioning with 150, 75 and 50-ns bunch<br />

spacing, important electron-cloud effects, like<br />

pressure rise, cryogenic heat load, beam instabilities<br />

or emittance growth, were observed. The main<br />

strategy to combat the LHC electron cloud relies on<br />

the surface conditioning arising from the chambersurface<br />

bombardment with cloud electrons. In a<br />

standard model, the conditioning state of the beampipe<br />

surface is characterized by three parameters: 1.<br />

the secondary emission yield; 2. the incident<br />

electron energy at which the yield is maximum; and<br />

3. the probability of elastic reflection of low-energy<br />

primary electrons hitting the chamber wall. Since at<br />

the LHC no in-situ secondary-yield measurements<br />

are available, we compare the relative local<br />

pressure-rise measurements taken for different beam<br />

configurations against simulations in which surface<br />

parameters are scanned. This benchmark of<br />

measurements and these simulations is used to infer<br />

the secondary-emission properties of the beam-pipe<br />

�<br />

Classification 1: Circular Colliders<br />

2<br />

at different locations around the ring and at various<br />

stages of the surface conditioning. In this paper we<br />

present the methodology and first results from<br />

applying the technique to the LHC.<br />

Sub Classification: A01 Hadron Colliders<br />

Poster Panel 3<br />

ID: 3732 - TUPZ003<br />

Simulation of Electron-cloud Build-Up for the<br />

Cold Arcs of the LHC and Comparison with<br />

Measured Data, Georfrey Humberto Israel Maury<br />

Cuna, Jesús Guillermo Contreras Nuño<br />

(CINVESTAV, Mérida), Gianluigi Arduini,<br />

Giovanni Rumolo, Laurent Tavian, Walter Venturini<br />

Delsolaro, Frank Zimmermann (CERN, Geneva) -<br />

The electron cloud generated by synchrotron<br />

radiation or residual gas ionization is a concern for<br />

LHC operation and performance. We report the<br />

results of simulations studies which examine the<br />

electron cloud build-up, at injection energy, at 4<br />

TeV and at 7 TeV for various operation parameters,<br />

e.g. different bunch spacings. In particular we<br />

determine the value of the secondary emission yield<br />

corresponding to the multipacting threshold, and<br />

investigate the electron density, electron flux, and<br />

heat load as a function of bunch intensity for<br />

dipoles, quadrupoles, and field-free regions. We also<br />

include a comparison between simulations results<br />

and measured heat-load data from the LHC<br />

scrubbing runs in 2010 and 2011.<br />

Sub Classification: A01 Hadron Colliders<br />

Poster Panel 4<br />

ID: 3326 - THPZ011<br />

Dynamic Aperture Optimization at BEPCII<br />

Storage Rings, Zhe Duan, Qing Qin (IHEP Beijng)<br />

- The upgrade machine of the Beijing Electron-<br />

Positron Collider (BEPCII) has reached about 2/3 of<br />

its design luminosity. Further increase in its<br />

efficiency requires a better dynamic aperture, which<br />

is currently the bottle neck of the beam lifetime.<br />

With only chromatic sextupoles placed in the arc<br />

area and no local compensation in the low beta<br />

insertion, the current 4 groups scheme of sextupole<br />

configuration seems not good enough. Instead, 18<br />

groups of sextupoles are optimized with genetic<br />

algorithm and a better result of dynamic aperture is<br />

obtained.<br />

Sub Classification: A02 Lepton Colliders


Poster Panel 5<br />

ID: 3311 - THPZ001<br />

Spin Dynamic Tool Developments and Study<br />

Regarding the Super-B Project, Nicolas Monseu<br />

(LPSC, Grenoble Cedex), Francois Meot (BNL,<br />

Upton, Long Island, New York), Jean-Marie De<br />

Conto (LPSC, Grenoble), Ulrich Wienands (SLAC,<br />

Menlo Park, California) - The study of polarization<br />

is essential for e+/e- colliders like the SuperB<br />

machine. The ZGOUBI integrator is a good and<br />

universal tool for particle tracking as well as spin<br />

tracking, and takes into account all machine realistic<br />

aspects, like real fields, non-linearities, fringing<br />

fields or misalignments. We present ZGOUBI<br />

implementation and the methods carried out to<br />

estimate invariant spin field and beam polarization<br />

evolution on some simple models (for validation)<br />

and on SuperB, and we investigate for some specific<br />

polarization behavior.<br />

Sub Classification: A02 Lepton Colliders<br />

Poster Panel 6<br />

ID: 3985 - THPZ009<br />

Beam Background Simulation for<br />

SuperKEKB/Belle-II, Hiroshi Nakano (Tohoku<br />

University, Sendai), Hiroyuki Nakayama (KEK,<br />

Tsukuba) - The Belle experiment is now being<br />

upgraded to the Belle II experiment designed for a<br />

40 times higher luminosity. Such a high luminosity<br />

is realized by the SuperKEKB collider where beaminduced<br />

background rates are expected to be much<br />

higher than those of KEKB. This poses a serious<br />

challenge for the design of the machine-detector<br />

interface. We have thus carried out a GEANT4based<br />

beam background simulation for Touschek<br />

effect and beam-gas scatterings. We describe the<br />

method of generating background particles and<br />

present the result of simulation.<br />

Sub Classification: A02 Lepton Colliders<br />

Poster Panel 7<br />

ID: 3154 - THPZ015<br />

LHeC Lattice Design, Miriam Fitterer,<br />

Oliver Sim Brüning, Helmut Burkhardt,<br />

Bernhard Johannes Holzer, John M. Jowett, Karl<br />

Hubert Mess, Thys Risselada (CERN, Geneva),<br />

Anke-Susanne Mueller (KIT, Karlsruhe), Max Klein<br />

(The University of Liverpool, Liverpool) - The<br />

Large Hadron Electron Collider (LHeC) aims at<br />

lepton-proton and lepton-nucleus collisions with<br />

�<br />

3<br />

centre of mass energies of 1-2 TeV at ep<br />

luminosities in excess of 10^33 cm^-2 s^-1. We<br />

present here a lattice design for the electron ring<br />

option, which meets the design parameters and also<br />

the constraints imposed by the integration of the new<br />

electron ring in the LHC tunnel.<br />

Sub Classification: A17 Electron-Hadron Colliders<br />

Poster Panel 8<br />

ID: 3801 - THPZ031<br />

Halo Scraping with Collimators in the LHC,<br />

Florian Burkart, Ralph Assmann, Roderik Bruce,<br />

Marija Cauchi, Daniel Deboy, Stefano Redaelli,<br />

Daniel Wollmann (CERN, Geneva) - The population<br />

of the beam halo has been measured in the LHC<br />

with beam scraping experiments. Primary<br />

collimators of the LHC collimation system were<br />

used to scrape the beam halo at different statuses of<br />

the machine (injection, top energy, separated and<br />

colliding beams). In addition these measurements<br />

were used to calibrate the beam loss monitor signals<br />

to loss rates at the primary collimators. Within this<br />

paper the halo scraping method, the measured halo<br />

distribution and the calibration factors are presented<br />

and compared to theoretical predictions.<br />

Sub Classification: T19 Collimation<br />

Poster Panel 9<br />

ID: 3800 - THPZ035<br />

Semi-automatic Beam-based Alignment<br />

Algorithm for the LHC Collimation System,<br />

Gianluca Valentino, Nicholas Sammut (CERN,<br />

Geneva; University of Malta, Msida), Ralph<br />

Assmann, Stefano Redaelli, Daniel Wollmann<br />

(CERN, Geneva) - Full beam-based alignment of the<br />

LHC collimation system was a lengthy procedure as<br />

the collimators were set up manually. A yearly<br />

alignment campaign has been sufficient for now,<br />

although in future this may lead to a decrease in the<br />

cleaning efficiency if machine parameters such as<br />

the beam orbit drift over time. Automating the<br />

collimator setup procedure can allow for more<br />

frequent alignments, therefore reducing this risk.<br />

This paper describes the design and testing of a<br />

semi-automatic algorithm as a first step towards a<br />

fully automatic setup. Its implementation in the<br />

collimator control software and future plans are<br />

described.<br />

Sub Classification: T19 Collimation


�<br />

Classification 2: Synchrotron Light Sources and FELs<br />

Poster Panel 10<br />

ID: 3482 - THPC045<br />

Design of a Compact Storage Ring for the TTX,<br />

Haisheng Xu, Wenhui Huang, Chuanxiang Tang<br />

(TUB, Beijing), Shyh-Yuan Lee (IUCEEM,<br />

Bloomington, Indiana) - We study a compact storage<br />

ring with circumference 3-m, 4 dipoles, and two<br />

quadrupoles for the Tsinghua Thomson scattering Xray<br />

(TTX) source. The effects of Touschek lifetime,<br />

rf system requirement, the Intra-beam scattering<br />

(IBS) and coherent synchrotron radiation (CSR) will<br />

be addressed. A top-up injection system will be<br />

designed to maximize the Photon flux. Conceptual<br />

laser cavity to enhance photon flux will be<br />

discussed. Expected performance of the compact Xray<br />

source will be presented.<br />

Sub Classification: A05 Synchrotron Radiation<br />

Facilities<br />

Poster Panel 11<br />

ID: 2936 - THPC006<br />

Experiments to Measure Electron Beam Energy<br />

using Spin Depolarization Method on SOLEIL<br />

Storage Ring, Jianfeng Zhang, Lodovico<br />

Cassinari, Marie Labat, Amor Nadji, Laurent<br />

Stanislas Nadolski, Dominique Pedeau (SOLEIL,<br />

Gif-sur-Yvette) - The SOLEIL storage ring electron<br />

beam energy was measured using spin<br />

depolarization method. The electron polarization<br />

was simulated using the SLIM code. The<br />

experimental results demonstrate that polarization<br />

build up time is 17 minutes as expected by the<br />

simulation and the depolarization process was also<br />

observed. The beam was depolarized using an AC<br />

shaker and the depolarization was monitored using<br />

DCCT and beam loss monitors. The problems to<br />

precisely determine the beam energy due to the wide<br />

resonance widths are discussed.<br />

Sub Classification: A05 Synchrotron Radiation<br />

Facilities<br />

Poster Panel 12<br />

ID: 4494 - THPC100<br />

Full Temporal Reconstruction using an<br />

Advanced Longitudinal Diagnostic at the SPARC<br />

FEL, Gabriel Marcus, James Rosenzweig (UCLA,<br />

Los Angeles, California), Luca Giannessi (ENEA<br />

C.R. Frascati, Frascati (Roma)), Massimo Ferrario<br />

(INFN/LNF, Frascati (Roma)) - The Production of<br />

ultra-short (sub 100 fs) single-spike radiation<br />

4<br />

possessing full longitudinal coherence from a freeelectron<br />

laser (FEL) has been the subject of intense<br />

study. The diagnosis of said pulses has proven to be<br />

challenging. A Frequency-Resolved Optical Gating<br />

(FROG) diagnostic has been developed and tested at<br />

UCLA, which has the capability of providing a<br />

longitudinal reconstruction of these ultra-fast pulses.<br />

This paper reports the results of the application of<br />

the diagnostic at the SPARC FEL facility for initial<br />

seeding experiments.<br />

Sub Classification: A06 Free Electron Lasers<br />

Poster Panel 13<br />

ID: 4368 - THPC102<br />

Two-color IFEL Microbunching at Neptune<br />

Laboratory, Finn O'Shea, Pietro Musumeci, James<br />

Rosenzweig (UCLA, Los Angeles, California) - We<br />

introduce the 2-color microbunching experiment to<br />

be performed at the UCLA Neptune Laboratory. We<br />

will use a new cryogenic undulator and seed the<br />

inverse free electron laser with two closely spaced<br />

CO2 laser frequencies. The result is significant<br />

bunching at THz frequencies. The technique is<br />

potentially useful for prebunching electron beams at<br />

frequencies that have no available solid state or gas<br />

lasers.<br />

Sub Classification: A06 Free Electron Lasers<br />

Poster Panel 14<br />

ID: 4082 - THPC087<br />

Saturation Effect on VUV Coherent Harmonic<br />

Generation at UVSOR-II, Takanori Tanikawa,<br />

Masahiro Adachi, Masahiro Katoh, Jun-ichiro<br />

Yamazaki, Heishun Zen (UVSOR, Okazaki),<br />

Masahito Hosaka, Yoshitaka Taira, Naoto<br />

Yamamoto (Nagoya University, Nagoya) - Light<br />

source technologies based on laser seeding are under<br />

development at the UVSOR-II electron storage ring.<br />

In the past experiments, we have succeeded in<br />

generating coherent harmonics (CHs) in deep<br />

ultraviolet (UV) and vacuum UV (VUV) region and<br />

also in generating CH with variable polarizations in<br />

deep UV*. In previous conference, we reported an<br />

introduction of new-constructed spectrometer for<br />

VUV and results of spectra measurement, undulator<br />

gap dependence, and injection laser power<br />

dependence on VUV CHs**. This time we have<br />

successfully observed saturation on CHs intensities<br />

and have found some interesting phenomena in<br />

different harmonic orders. In this conference, we


will discuss the results of some systematic<br />

measurements and those analytical and particle<br />

tracking simulations***.<br />

* M. Labat et al., Phys. Rev. Lett. 101 (2008)<br />

164803.<br />

** T. Tanikawa et al., Proc. IPAC'10, TUPE029, p.<br />

2206 (2010).<br />

*** T. Tanikawa et al., Appl. Phys. Express 3<br />

(2010) 122702. Funding Agency<br />

Sub Classification: A06 Free Electron Lasers<br />

Poster Panel 15<br />

ID: 3711 - THPC089<br />

Study of Terahertz Free Electron Laser<br />

Oscillator based on Electrostatic <strong>Accelerator</strong>,<br />

Ailin Wu (USTC/NSRL, Hefei, Anhui) - For the<br />

terahertz radiation sources provide wide applications<br />

in medical science, material science and industrial, a<br />

compact, wavelength tunable and high-power THz<br />

source attracted much attention in many<br />

laboratories. In this paper, we give a primary study<br />

of a compact electrostatic accelerator driven THz<br />

FEL (EA-THz) and its basic design parameters. The<br />

feasibility study is carried out using FELO code.<br />

The initial results show that such EA-FEL will be a<br />

promising compact and powerful THz source.<br />

Sub Classification: A06 Free Electron Lasers<br />

Poster Panel 16<br />

ID: 3936 - TUPO013<br />

Development of Pulse Width Measurement<br />

Techniques in a Picosecond Range of Ultra-short<br />

Gamma Ray Pulses, Yoshitaka Taira, Masahito<br />

Hosaka, Kazuo Soda, Naoto Yamamoto (Nagoya<br />

University, Nagoya), Takanori Tanikawa (UVSOR,<br />

Okazaki), Masahiro Adachi, Masahiro Katoh,<br />

Heishun Zen (UVSOR, Okazaki; Sokendai -<br />

Okazaki, Okazaki, Aichi) - We are developing the<br />

ultra-short gamma ray pulse source with the energy<br />

of MeV region based on laser Compton scattering at<br />

the 750 MeV electron storage ring, UVSOR-II.<br />

Gamma rays with pulse width of sub-picosecond<br />

range can be generated by injecting femtosecond<br />

laser pulses into the electron beam from the vertical<br />

90-degree direction* because the electron beam<br />

circulating in the storage ring is focused more tightly<br />

in the vertical direction than in the longitudinal<br />

direction. The energy, intensity, and pulse width of<br />

the gamma rays can be tuned by changing the<br />

collision angle between the electron beam and the<br />

laser. We are developing pulse width measurement<br />

techniques of ultra-short gamma ray pulses at<br />

present. As the first step of the pulse width<br />

�<br />

5<br />

measurement, we used a fast response photodetector,<br />

Geiger-mode APD, the time resolution of which is<br />

few hundreds picoseconds. Although we cannot<br />

measure the pulse width of the gamma rays with<br />

sub-picosecond range using this detector, we could<br />

measure the pulse width of the gamma rays as 430<br />

ps or less by measuring the timing of Cherenkov<br />

radiations generated from the gamma rays.<br />

* Y. Taira et al., Nucl. Instrum. Meth. A, in press,<br />

2010. Funding Agency This work was supported<br />

by Grants-in-Aid for Scientific Research from Japan<br />

Society for the Promotion of Science (JSPS).<br />

Sub Classification: A14 Advanced Concepts<br />

Poster Panel 17<br />

ID: 3212 - TUPO006<br />

Design of a Dispersive Beam Transport Line for<br />

Laser Wakefield <strong>Accelerator</strong>s,<br />

Christina Widmann, Veronica Afonso Rodriguez,<br />

Tilo Baumbach, Axel Bernhard, Peter Peiffer (KIT,<br />

Karlsruhe), Malte Kaluza, Maria Nicolai (IOQ,<br />

Jena), Robert Rossmanith (Karlsruhe Institute of<br />

Technology (KIT), Karlsruhe) - Laser wakefield<br />

accelerators (LWFA) emit electrons with energies of<br />

a few 100 MeV at very short bunch lengths while<br />

having a compact design. However, electron<br />

bunches from LWFA show a larger energy spread<br />

than those of conventional accelerators. This is a<br />

challenge when using these bunches e.g. to generate<br />

radiation in an undulator. A possible strategy to cope<br />

with that is to spectrally disperse the bunch and<br />

match the resulting spatial distribution with a<br />

spatially varying undulator field amplitude. For<br />

realizing the dispersion a pair of dipole magnets is<br />

used. The electrons leaving this dipole chicane have<br />

to meet certain requirements imposed by the<br />

undulator: In the deflection plane the beam has to be<br />

collimated and its energy distribution must match<br />

the undulator field. In the other transversal plane the<br />

beam has to be focussed on the center of the<br />

undulator keeping the value of the beta function<br />

small. To include this in the compact design of the<br />

setup, a combination of specially designed<br />

quadrupole and sextupole magnets is employed. In<br />

this contribution the design of the setup and the<br />

results of the particle tracking through this chicane<br />

are presented.<br />

Sub Classification: A14 Advanced Concepts


Poster Panel 18<br />

ID: 2809 - TUPO034<br />

Longitudinal Stability of ERL with Two<br />

Accelerating RF Structures,<br />

Yaroslav V. Getmanov, Oleg A. Shevchenko (BINP<br />

SB RAS, Novosibirsk), Nikolay Vinokurov (BINP<br />

SB RAS, Novosibirsk; NSU, Novosibirsk) - Modern<br />

ERL projects use superconductive accelerating RF<br />

structures. Their RF quality is typically very high.<br />

Therefore, the RF voltage induced by electron beam<br />

is also high. In ERL the RF voltage induced by the<br />

accelerating beam is almost canceled by the RF<br />

voltage induced by the decelerating beam. But, a<br />

small variation of the RF voltage may cause the<br />

deviations of the accelerating phases. These<br />

deviations then may cause further voltage variation.<br />

Thus the system may be unstable. The stability<br />

conditions for ERL with one accelerating structure<br />

are well known [*, **]. The ERL with split RF<br />

structure was discussed recently [***, ****]. The<br />

stability conditions for such ERLs are discussed in<br />

this paper.<br />

* L. Merminga et al.,Annu.Rev.Nucl.Part.Sci. 53<br />

(2003) 387.<br />

** N.A. Vinokurov et al.,Proc. SPIE 2988 (1997)<br />

221.<br />

*** D. Douglas, ICFA BD-Nl 26 (2001) 40.<br />

**** N.A. Vinokurov et al.,Proc. IPAC’10.<br />

Sub Classification: A16 Energy Recovery Linacs<br />

(ERLs)<br />

Poster Panel 19<br />

ID: 3823 - THPC113<br />

Slice Emittance Measurements for Different<br />

Bunch Charges at PITZ, Yevgeniy Ivanisenko,<br />

Galina Asova, Hans-Juergen Grabosch, Matthias<br />

Gross, Levon Hakobyan, Igor Vladimirovich Isaev,<br />

Martin Khojoyan, Guido Klemz, Mikhail<br />

Krasilnikov, Mahmoud Mahgoub, Dmitriy<br />

Malyutin, Anne Oppelt, Bagrat Petrosyan, Dieter<br />

Richter, Sakhorn Rimjaem, Andrey Shapovalov,<br />

Frank Stephan, Grygorii Vashchenko, Steffen We<br />

IDinger (DESY Zeuthen, Zeuthen) - The successful<br />

operation of the Free electron LASer in Hamburg<br />

(FLASH), DESY, brings up the interest in further<br />

broadening the spectrum of possible applications<br />

also for the upcoming European XFEL . Hence the<br />

electron beam properties required for the lasing<br />

should also be and tested in a broad range of values<br />

already on the level of the injector. The Photo<br />

Injector Test facility in Zeuthen (PITZ), DESY,<br />

characterizes the photo injectors for FLASH and the<br />

XFEL. The main study involves the transverse<br />

�<br />

6<br />

projected emittance optimization for different beam<br />

conditions. Beside the projected emittance, the PITZ<br />

setup allows to measure the transverse emittance<br />

with a sub-bunch longitudinal resolution. This slice<br />

emittance diagnostics is based on the usage of<br />

bunches with a narrow linear energy correlation of<br />

the longitudinal phase space. Then the bunch is<br />

swept vertically with the dipole magnet. Part of the<br />

bunch is cut out and the horizontal emittance is<br />

measured. This report includes the results of the<br />

recent slice emittance measurements for different<br />

bunch charges. Funding Agency<br />

Sub Classification: T02 Lepton Sources<br />

Poster Panel 20<br />

ID: 4440 - THPC186<br />

Heat Load for the APS Superconducting<br />

Undulator, Laura Boon, Arthur Garfinkel (Purdue<br />

University, West Lafayette, Indiana), Katherine C.<br />

Harkay (ANL, Argonne) - The APS Upgrade calls<br />

for the development and commissioning of a<br />

superconducting undulator (SCU) at the Advanced<br />

Photon Source (APS), a 7-GeV electron<br />

synchrotron. The first SCU will be installed in June<br />

2012. Until then, simulations such as SYNRAD3D<br />

will be used to understand and reduce the heat load<br />

on the cryo-system from primary and secondary<br />

photons. Current calculations predict that primary<br />

photons will distribute 0.5W/m on the chamber<br />

walls of the cryostat. SYNRAD3D will be used to<br />

calculate the ratio of primary and secondary photons<br />

to calculate the heat load due to secondary photons.<br />

Previous simulations were of only one sector of the<br />

APS accelerator. Simulated here are multiple<br />

sectors, to include photons back scattered from<br />

downstream photon absorbers.<br />

Funding Agency: Work supported by U.S.<br />

Department of Energy, Office of Science, Office of<br />

Basic Energy Sciences, under Contract No. DE-<br />

AC02-06CH11357.<br />

Sub Classification: T15 Undulators and Wigglers<br />

Poster Panel 21<br />

ID: 3324 - THPC175<br />

Spectrum Analysis of Arbitrary Strength<br />

Parameter in Various Insertion Device,<br />

Sei-Da Chen, Tseng-Ming Uen (NCTU, Hsinchu),<br />

Ching-Shiang Hwang (NSRRC, Hsinchu) - An<br />

insertion device (ID) with medium strength<br />

parameter was hard to be defined as a wiggler or an<br />

undulator. Usually, this kind of ID was classified<br />

according to the user’s definition and to select the<br />

spectrum calculation formula of wiggler or


undulator. The spectrum calculation formula for<br />

wiggler or undulator is quite difference and<br />

consequently obtain a big different flux density by<br />

using the same strength parameter. So, it is no way<br />

that the spectrum calculation of them is consistent.<br />

Therefore, a universal formula will be developed for<br />

the spectrum analysis for the different kinds of<br />

insertion devices that is with large different strength<br />

parameter (deflection parameter). Consequently, a<br />

modified spectrum calculation formula of ID with<br />

medium strength parameter was studied by<br />

reviewing the difference of existing spectrum<br />

formulas. The familiar formula of calculating<br />

undulator spectrum was modified and can be used<br />

on ID with arbitrary strength parameter. The<br />

algorithm of formula modification was described.<br />

Some relative issue, like the effect of phase error<br />

and energy spread, and taper undulator were also<br />

discussed herein.<br />

Sub Classification: T15 Undulators and Wigglers<br />

Poster Panel 22<br />

ID: 3267 - THPC168<br />

A New Approach on Field Error Compensation<br />

for Superconducting Undulator,<br />

Somjai Chunjarean (PAL, Pohang, Kyungbuk),<br />

Ching-Shiang Hwang, Jyh-Chyuan Jan (NSRRC,<br />

Hsinchu), Helmut Wiedemann (SLAC, Menlo Park,<br />

California) - To reach higher photon energies in the<br />

region of soft or hard x-rays with high photon beam<br />

brightness in low energy storage rings,<br />

superconducting undulators with very short period<br />

length and high magnetic field strength are required.<br />

Because undulator radiation comes in a line<br />

spectrum, photons up to the 7th harmonic are<br />

desired. The photon brightness in such harmonics is<br />

strongly dependent on perfect periodicity of the<br />

magnetic field. Such imperfections also appear in<br />

conventional permanent material undulators, which<br />

can be corrected by well developed and efficient<br />

shimming. Unfortunately, this method cannot be<br />

applied to superconducting undulators. Therefore,<br />

we present a new approach to field corrections by<br />

modification of the magnetic field saturation in each<br />

pole. In this paper it is shown that this approach can<br />

reduce not only the magnetic field error but also<br />

greatly improves phase errors from period to period.<br />

The proposed method works quite local with only<br />

small perturbations in neighboring poles. The<br />

�<br />

7<br />

tenability is preserved for most of the field<br />

excitations and is reduced only at extreme<br />

parameters.<br />

Sub Classification: T15 Undulators and Wigglers<br />

Poster Panel 23<br />

ID: 3075 - THPC159<br />

Factory Acceptance Test of COLDDIAG: A Cold<br />

Vacuum Chamber for Diagnostics, Stefan Gerstl,<br />

Tilo Baumbach, Sara Casalbuoni, Andreas<br />

Wolfgang Grau, Michael Hagelstein, Tomas<br />

Holubek, David Saez de Jauregui (Karlsruhe<br />

Institute of Technology (KIT), Karlsruhe), Cristian<br />

Boffo, Gunther Sikler (BNG, Würzburg), Vincent<br />

Baglin (CERN, Geneva), James Clarke, Roger<br />

Michael Jones, Duncan Scott (Cockcroft Institute,<br />

Warrington, Cheshire), Matthew Peter Cox, Jos<br />

Chris Schouten (Diamond, Oxfordshire), Roberto<br />

Cimino, Mario Commisso, Andrea Mostacci, Bruno<br />

Spataro (INFN/LNF, Frascati (Roma)), Erik Jan<br />

Wallén (MAX-lab, Lund), Ralf Weigel (Max-Planck<br />

Institute for Metal Research, Stuttgart), Thomas<br />

William Bradshaw (STFC/RAL, Chilton, Didcot,<br />

Oxon), Ian Reginald Roy Shinton (UMAN,<br />

Manchester) - Superconductive insertion devices<br />

(IDs) have higher fields for a given gap and period<br />

length compared with the state-of-the-art technology<br />

of permanent magnet IDs. One of the still open<br />

issues for the development of superconductive<br />

insertion devices is the understanding of the heat<br />

intake from the electron beam. With the aim of<br />

measuring the beam heat load to a cold bore and the<br />

hope to gain a deeper understanding in the<br />

underlying mechanisms, a cold vacuum chamber for<br />

diagnostics was built. It is equipped with the<br />

following instrumentation: retarding field analyzers<br />

to measure the electron flux, temperature sensors to<br />

measure the beam heat load, pressure gauges, and<br />

mass spectrometers to measure the gas content. The<br />

flexibility of the engineering design will allow the<br />

installation of the cryostat in different synchrotron<br />

light sources. The installation in the storage ring of<br />

the Diamond Light Source is foreseen in November<br />

2011. Here we report about the technical design of<br />

this device, the factory acceptance test and the<br />

planned measurements with electron beam.<br />

Sub Classification: T15 Undulators and Wigglers


�<br />

Classification 3: Linear Colliders, Lepton <strong>Accelerator</strong>s and New Acceleration Techniques<br />

Poster Panel 24<br />

ID: 3003 - TUPC011<br />

Development of Striplines for the CLIC Pre-<br />

Damping and Damping Ring Kickers,<br />

Carolina Belver-Aguilar, Angeles Faus-Golfe<br />

(IFIC, Valencia), Michael John Barnes (CERN,<br />

Geneva), Fernando Toral (CIEMAT, Madrid) - The<br />

Compact Linear Collider (CLIC) study is exploring<br />

the scheme for an electron-positron collider with<br />

high luminosity and a nominal center-of-mass<br />

energy of 3 TeV: CLIC would complement LHC<br />

physics in the multi-TeV range. The CLIC design<br />

relies on the presence of Pre-Damping Rings (PDR)<br />

and Damping Rings (DR) to achieve, through<br />

synchrotron radiation, the very low emittance<br />

needed to fulfil the luminosity requirements. The<br />

specifications for the kicker systems are very<br />

challenging and include very low beam coupling<br />

impedance and excellent field homogeneity:<br />

striplines have been chosen for the kicker elements.<br />

Analytical calculations have been carried out to<br />

determine the effect of tapering upon the high<br />

frequency beam coupling impedance. In addition<br />

detailed numerical modeling of the field<br />

homogeneity has been performed and the sensitivity<br />

of the homogeneity to various parameters, including<br />

stripline cross-section, has been studied. This paper<br />

presents the main conclusions of the beam<br />

impedance calculations and field homogeneity<br />

predictions.<br />

Sub Classification: A03 Linear Colliders<br />

Poster Panel 25<br />

ID: 3993 - TUPC001<br />

Recent Developments in Beam-beam Simulations<br />

Relevant for Multi-TeV Linear Colliders,<br />

Jakob Esberg, Ulrik Ingerslev Uggerhøj (Aarhus<br />

University, Aarhus), Daniel Schulte (CERN,<br />

Geneva) - The design of a detector and post<br />

collisional line of a future linear collider calls for<br />

detailed knowledge of the beam-beam dynamics at<br />

the interaction point. We here describe the<br />

implementation and results of new simulation tools<br />

in the program GUINEA-PIG. The subjects are<br />

direct trident production relevant in the deep<br />

quantum-regime, incoherent muon generation,<br />

synchrotron radiation from secondary particles and<br />

depolarization effects. We choose beam parameters<br />

in the range relevant for CLIC and comment on the<br />

implications for the design of such a machine.<br />

Sub Classification: A03 Linear Colliders<br />

8<br />

Poster Panel 26<br />

ID: 2893 - TUPC014<br />

System Control for the CLIC Main Beam<br />

Quadrupole Stabilization and Nano-positioning,<br />

Stef Janssens, Kurt Artoos, Christophe Collette,<br />

Pablo Fernandez Carmona, Michael Guinchard,<br />

Claude Hauviller, Andrey Kuzmin, Raphael Leuxe,<br />

Juergen Pfingstner, Daniel Schulte, Jochem<br />

Snuverink (CERN, Geneva) - The conceptual design<br />

of the active stabilization and nano-positioning of<br />

the CLIC main beam quadrupoles was validated in<br />

models and experimentally demonstrated on test<br />

benches. Although the mechanical vibrations were<br />

reduced to within the specification of 1.5 nm at 1<br />

Hz, additional input for the stabilization system<br />

control was received from integrated luminosity<br />

simulations that included the measured stabilization<br />

transfer functions. Studies are ongoing to obtain a<br />

transfer function which is more compatible with<br />

beam based orbit feedback; it concerns the controller<br />

layout, new sensors and their combination. In<br />

addition, the gain margin must be increased in order<br />

to reach the requirements from a higher vibration<br />

background. For this purpose, the mechanical<br />

support is adapted to raise the frequency of some<br />

resonances in the system and the implementation of<br />

force sensors is considered. Furthermore, this will<br />

increase the speed of repositioning the magnets<br />

between beam pulses. This paper describes the<br />

improvements and their implementation from a<br />

controls perspective.<br />

Sub Classification: A03 Linear Colliders<br />

Poster Panel 27<br />

ID: 3108 - TUPC036<br />

S-band ps Pulse Photoinjector for THz Radiation<br />

Source, Sergey Markovich Polozov,<br />

Taras Vladimirovich Bondarenko (MEPhI,<br />

Moscow) - S-band photoinjectors with ps pulse are<br />

becoming promising as e-guns for high-intensity<br />

sub-mm wavelength pulse source. Development of<br />

accelerating system for photoinjector with ps bunch<br />

is reported. The main aim is to develop a model of<br />

accelerating structure that provide top accelerating<br />

fields in respect to high electric strength and low RF<br />

power uses. The accelerating structures consisting of<br />

1.6 cell of disk-loaded waveguide (DLW), 3 cells<br />

and 2 half-cells of DLW, 7 cels and 2 half-cells of<br />

DLW and accelerating structure based on running<br />

wave resonator with 7 cells and 2 half-cells of DLW


are studying. The resonant models of these<br />

structures and the structures with power ports were<br />

designed. Electrodynamics characteristics, electric<br />

field distribution for all models were acquired.<br />

Accelerating structure consisting of 1.6 cells will<br />

operate in pi mode of standing wave, all other<br />

structures operate in pi/2 mode traveling wave.<br />

Accelerating structure based on running wave<br />

resonator with 7 cells and 2 half-cells of DLW has<br />

most suitable electrodynamics characteristics and<br />

field distribution for sub-mm pulse source according<br />

to simulation results.<br />

Sub Classification: A08 Linear <strong>Accelerator</strong>s<br />

Poster Panel 28<br />

ID: 4374 - MOPZ033<br />

Proton Contamination Studies in the Muon<br />

Ionization Cooling Experiment, Summer Blot<br />

(University of Chicago, Chicago, Illinois),<br />

Rob Roy MacGregor Fletcher (UCR, Riverside,<br />

California) - The Muon Ionization Cooling<br />

Experiment (MICE) aims to demonstrate transverse<br />

beam emittance reduction for a muon beam. To<br />

create these muons, a titanium target is dipped into<br />

the ISIS proton accelerator at Rutherford Appleton<br />

Laboratory (UK) to create pions, which are<br />

transported and decay to muons in the MICE<br />

beamline. Beam particle identification and triggering<br />

is performed using time of flight (ToF) detectors.<br />

When running the MICE beamline with positive<br />

polarity, protons produced in the target contaminate<br />

the muon beam with a sufficiently high rate to<br />

saturate the TOF detectors. Polyethylene sheets of<br />

varying thicknesses were installed to absorb the<br />

proton impurities in the beam. Studies with pion<br />

beams at momenta of 140, 200, and 240MeV/c were<br />

performed with different proton absorber<br />

thicknesses. The results of these studies show good<br />

agreement with theoretical range plots and will be<br />

presented.<br />

Sub Classification: A09 Muon <strong>Accelerator</strong>s and<br />

Neutrino Factories<br />

Poster Panel 29<br />

ID: 4198 - MOPZ014<br />

MAUS: MICE Analysis User Software,<br />

Christopher Douglas Tunnell (JAI, Oxford) - The<br />

Muon Ionization Cooling Experiment (MICE) is<br />

unique because it measures accelerator physics<br />

quantities using particle physics methods. It follows<br />

that the software that forms the theoretical model of<br />

MICE needs to be able to not only propagate beam<br />

envelopes and optical parameters but also model<br />

�<br />

9<br />

detector responses and matter effects for cooling.<br />

MICE addresses this dichotomy with the software<br />

framework MAUS in order to maximize its physics<br />

sensitivity whilst providing the conveniences of, for<br />

example, a common data structure. The diversity of<br />

challenges that MICE provides from the analysis<br />

perspective means that appropriately defining the<br />

software scope and layout is critical to the<br />

correctness and maintainability of the final<br />

accelerator physics analyses. MICE has structured<br />

its code into a Map-Reduce framework to enable<br />

better parallelization whilst also introducing unit,<br />

functional, and integration tests to ensure code<br />

reliability and correctness. These methods can apply<br />

to other experiments.<br />

Sub Classification: A09 Muon <strong>Accelerator</strong>s and<br />

Neutrino Factories<br />

Poster Panel 30<br />

ID: 3100 - TUPC046<br />

Alignment Tolerances for Vertical Emittance,<br />

Kent Peter Wootton, Roger Paul Rassool, Geoffrey<br />

Taylor (The University of Melbourne, Melbourne),<br />

Mark James Boland, Rohan Dowd, Gregory Scott<br />

LeBlanc, Yaw-Ren Eugene Tan (ASCo, Clayton,<br />

Victoria), Yannis Papaphilippou (CERN, Geneva) -<br />

Alignment tolerances for the CLIC main damping<br />

ring magnetic lattice elements are presented.<br />

Tolerances are defined by the design equilibrium<br />

vertical emittance of 1 pm rad. The sensitivity of the<br />

uncorrected lattice to magnet misalignments is<br />

presented. Misalignments considered included<br />

quadrupole vertical offsets and rolls, sextupole<br />

vertical offsets, and main dipole rolls. Seeded<br />

simulations were conducted in MAD-X, and<br />

compared with expectation values calculated from<br />

theory. The lattice was found to be sensitive to<br />

betatron coupling as a result of sextupole vertical<br />

offsets in the arcs. Alignment tolerances, BPM and<br />

corrector requirements are presented also. For the<br />

same misalignment types, the equilibrium emittance<br />

of the corrected lattice is simulated. These are<br />

compared with expectation values calculated from<br />

theory. The vertical alignment tolerance of arc<br />

sextupoles is again demanding.<br />

Sub Classification: A10 Damping Rings<br />

Poster Panel 31<br />

ID: 3360 - WEPZ002<br />

Chromatic Aberration and Transmission of<br />

Laser Accelerated Protons Focused by a<br />

Solenoid, Husam Yousef Al-Omari,<br />

Ulrich Ratzinger (IAP, Frankfurt am Main), Ingo


Hofmann (GSI, Darmstadt) - Chromatic aberrations<br />

and emittance growth in the laser proton experiment<br />

LIGHT at GSI are calculated numerically from the<br />

proton trajectories through a given solenoid based<br />

on geometrical conditions. Transmission of protons<br />

through an aperture located behind solenoid at the<br />

focal spot is studied numerically. Different codes<br />

were employed in this study: TRACE 3D, Parmila,<br />

TraceWin as well as comparison with a Matlab<br />

program simulating accurate trajectories through the<br />

solenoid. The results show the dependence of<br />

chromatic aberration and emittance growth on the<br />

distance between laser-target and solenoid, which<br />

allow using an aperture behind the solenoid as<br />

energy filter of the beam.<br />

Sub Classification: A13 New Acceleration<br />

Techniques<br />

Poster Panel 32<br />

ID: 4444 - WEPZ008<br />

Experimental Plans to Explore Dielectric<br />

Wakefield Acceleration in the THz Regime,<br />

Francois Lemery (Northern Illinois University,<br />

DeKalb, Illinois) - Dielectric wakefield accelerators<br />

have shown great promise toward high-gradient<br />

acceleration. We investigate tow experiments in<br />

preparation to explore the performance of<br />

cylindrically-symmetric and slab-shaped dielectricloaded<br />

waveguides. The planned experiments at<br />

Fermilab and DESY will use unique pulse shaping<br />

capabilities offered at these facilities. The<br />

superconducting test accelerator at FNAL will<br />

ultimately provide flat beams with variable current<br />

profiles needed for enhancing the transformer ratio.<br />

The FLASH facility at DESY recently demonstrated<br />

the generation of a ramped round beam current<br />

profile that will enable us to explore the<br />

performance of cylindrically-symmetric structures.<br />

Finally both of these facilities incorporate<br />

superconducting linear accelerator that could<br />

generate bunch trains with closely spaced bunches<br />

thereby opening the exploration of dynamical effects<br />

in dielectric wakefield accelerators. We present the<br />

planned layout and simulated experimental<br />

performances.<br />

Funding Agency: This work was supported by the<br />

Defense Threat Reduction Agency, Basic Research<br />

Award \# HDTRA1-10-1-0051, to Northern Illinois<br />

University<br />

Sub Classification: A13 New Acc. Techniques<br />

Poster Panel 33<br />

ID:4163 - WEPZ030<br />

�<br />

10<br />

High-energy Electron Acceleration Research with<br />

a Capillary Plasma at GIST, Min-Seok Kim<br />

(APRI-GIST, Gwangju) - Compared with the<br />

conventional accelerators, laser-driven plasma<br />

accelerators have a much higher acceleration<br />

gradient of ~100 GeV/m and they can accelerate<br />

electrons to GeV level over a few centimeter<br />

distance. At GIST (Gwangju Institute of Science and<br />

Technology), we have ongoing research activities on<br />

laser-plasma acceleration using a capillary plasma<br />

source, where a high power laser pulse is optically<br />

guided in the cm–long capillary plasma with a<br />

parabolic density profile in the transverse direction.<br />

For this purpose, we developed several capillary<br />

plasma sources and tested them, which can provide a<br />

plasma density of ~1018 cm-3. In this poster, details<br />

about the capillary development and electron<br />

acceleration experiments in our group are presented.<br />

Sub Classification: A20 Plasma Wakefield<br />

Acceleration<br />

Poster Panel 34<br />

ID: 4334 - WEPZ034<br />

Resonant Plasma Wakefield Experiments at<br />

UCLA, Brendan Donald O'Shea, Atsushi<br />

Fukasawa, James Rosenzweig, Sergei Tochitsky<br />

(UCLA, Los Angeles, California), Bernhard Hidding<br />

(HHU, Duesseldorf; UCLA, Los Angeles), David<br />

Leslie Bruhwiler (Tech-X, Boulder, Colorado) -<br />

Present work in Laser Plasma <strong>Accelerator</strong>s focuses<br />

on a single laser pulse driving a non-linear wake in a<br />

plasma. Such single pulse regimes require ever<br />

increasing laser power in order to excite ever<br />

increasing wake amplitudes. Such high power pulses<br />

can be limited by instabilities as well engineering<br />

restrictions and experimental constraints on optics.<br />

Alternatively we present a look at resonantly driving<br />

plasmas using a laser pulse train. In particular we<br />

compare analytic, numerical and PIC simulation<br />

results to characterize a proposed experiment to<br />

measure the wake produced by four Gaussian laser<br />

pulses. The current progress depicts the interaction<br />

of 4 laser pulses of 3 ps FWHM, separated peak-topeak<br />

by 18 ps, each of normalized vector potential<br />

a0~0.7. Results confirm previous discourse (*,**)<br />

and show, for a given laser profile, a band pass like<br />

structure of choices for plasma density grouped<br />

around the so called single pulse resonant condition,<br />

ωp=π/t_fwhm.<br />

* Umstadter, D., et al, Phys. Rev. Lett. 72, 1224<br />

** Umstadter, D., et al, Phys. Rev. E 51, 3484<br />

Sub Classification: A20 Plasma Wakefield<br />

Acceleration


Poster Panel 35<br />

ID: 2926 - WEPS011<br />

Application of Orbit Response Matrix Method at<br />

CSNS/RCS, Yuwen An, Sheng Wang, Yuanyuan<br />

Wei (IHEP Beijing, Beijing) - China Spallation<br />

Neutron Source (CSNS) accelerator consists of an<br />

H- linac and a Rapid Cycling Synchrotron(RCS).<br />

RCS operates at 25Hz, accumulates 80MeV proton<br />

beam, and accelerates to 1.6GeV. Application of<br />

response matrix(RM) method to RCS has been<br />

studied. The closed orbit correction can be well<br />

performed by optimizing solution algorithm. To<br />

calibrate the lattice function, the fudge factors of<br />

quadrupoles, the offset of beam position monitors<br />

are obtained by using RM methods, and the study to<br />

improve the measurement accuracy has been done.<br />

The detailed simulation results in the study are<br />

shown in this paper.<br />

Sub Classification: A04 Circular <strong>Accelerator</strong>s<br />

Poster Panel 36<br />

ID: 2769 - WEPS012<br />

Commissioning of Slow Extraction in HIRFL-<br />

CSR, Jian Shi, Weiping Chai, Jie Li, Peng Li,<br />

Ruishi Mao, Jia Wen Xia, Jiancheng Yang, Da Yu<br />

Yin, Youjin Yuan (IMP, Lanzhou) - The HIRFL-<br />

CSR* contains a complex in cancer therapy**, and<br />

we realized the 1/3 order resonant slow extraction in<br />

May 2008. In order to improve the beam quality that<br />

required in the clinical treatment, we have<br />

performed 5 times machine study. The extraction<br />

efficiency has been improved to 65% by change the<br />

shape of the separatrix, and the spot size in the target<br />

is less than 3.5mm in FWHM, the spill uniformity<br />

we obtained excelled 97%.In the 5th time, we<br />

utilized the fast quadrupole to make a feedback, the<br />

spill quality been improved a lot. We report the<br />

latest commissioning result about the slow<br />

extraction and spill quality in HIRFL-CSR.<br />

* J.W. Xia, W.L. Zhan et al., Nuclear Instrum.<br />

Methods A 488, 11 (2002).<br />

** Y.J Yuan, High Power Laser and <strong>Particle</strong> Beams<br />

17(2), Feb 2005. Funding Agency<br />

Sub Classification: A04 Circular <strong>Accelerator</strong>s<br />

Poster Panel 37<br />

ID: 3087 - WEPS033<br />

Matching Laser Driven Proton Injectors to CH -<br />

Drift Tube Linacs, Ali Almomani, Martin Droba,<br />

Ulrich Ratzinger (IAP, Frankfurt am Main), Ingo<br />

�<br />

Classification 4: Hadron <strong>Accelerator</strong>s<br />

11<br />

Hofmann (GSI, Darmstadt; HIJ, Jena) -<br />

Experimental results and theoretical predictions in<br />

laser acceleration of protons achieved energies of ten<br />

to several tens of MeV. This study demonstrates the<br />

transporting and focusing of laser-accelerated 10<br />

MeV protons by a pulsed magnetic solenoid with a<br />

field gradient up to 18 T. The unique features of the<br />

protons distribution like extremely small emittances<br />

and high yield of the order of 10^13 protons per<br />

shot, make them attractive for study. The possibility<br />

of using these protons as a source of energetic ions<br />

for ion accelerators is addressed. With respect to<br />

transit energies, further acceleration by matching<br />

into rf linac seems adequate. The bunch injection<br />

into a proposed CH- structure is under investigation<br />

at IAP Frankfurt. Options and simulation tools are<br />

presented.<br />

Sub Classification: A08 Linear <strong>Accelerator</strong>s<br />

Poster Panel 38<br />

ID: 3576 - WEPS036<br />

First Coupled CH Power Cavity for the FAIR<br />

Proton Injector, Robert Brodhage, Christopher<br />

Fix, Holger Podlech, Ulrich Ratzinger (IAP,<br />

Frankfurt am Main), Gianluigi Clemente, Lars<br />

Groening (GSI, Darmstadt) - For the research<br />

program with cooled antiprotons at FAIR a<br />

dedicated 70 MeV, 70 mA proton injector is<br />

required. The main acceleration of this room<br />

temperature linac will be provided by six CH<br />

cavities operated at 325 MHz. Each cavity will be<br />

powered by a 2.5 MW Klystron. For the second<br />

acceleration unit from 11.5 MeV to 24.2 MeV a 1: 2<br />

scaled model has been built. Low level RF<br />

measurements have been performed to determine the<br />

main parameters and to prove the concept of coupled<br />

CH cavities. For this second tank technical and<br />

mechanical investigations have been performed in<br />

2010 to develop a complete technical concept for the<br />

manufacturing. In Spring 2011, the construction of<br />

the first power prototype has started. The main<br />

components of this cavity will be ready for<br />

measurements in summer 2011. At that time, the<br />

cavity will be tested with a preliminary aluminum<br />

drift tube structure, which will allow precise<br />

frequency and field tuning. This paper will report on<br />

the recent technical development and achievements.<br />

It will outline the main fabrication steps towards that<br />

novel type of proton DTL. Also first low level RF<br />

measurements are expected.


Sub Classification: A08 Linear <strong>Accelerator</strong>s<br />

Poster Panel 39<br />

ID: 3706 - WEPS038<br />

Development of CH-Cavities for the 17 MeV<br />

MYRRHA-Injector, Dominik Mäder, Horst Klein,<br />

Holger Podlech, Ulrich Ratzinger, Markus<br />

Vossberg, Chuan Zhang (IAP, Frankfurt am Main) -<br />

MYRRHA is conceived as an accelerator driven<br />

system (ADS) for transmutation of high level<br />

nuclear waste. The neutron source is created by<br />

coupling a proton accelerator of 600 MeV with a 4<br />

mA proton beam, a spallation source and a subcritical<br />

core. The IAP of Frankfurt University is<br />

responsible for the development of the 17 MeV<br />

injector operated at 176 MHz. The injector consists<br />

of a 1.5 MeV 4-Rod-RFQ and six CH-drifttubestructures.<br />

The first two CH-structures will be<br />

operated at room temperature and the other CHstructures<br />

are superconducting cavities assembled in<br />

one cryo-module. To achieve the extremely high<br />

reliability required by the ADS application, the<br />

design of the 17 MeV injector has been intensively<br />

studied, with respect to thermal issues, minimum<br />

peak fields and field distribution.<br />

Funding Agency European Union FP7 MAX<br />

Contract Number 269565<br />

Sub Classification: A08 Linear <strong>Accelerator</strong>s<br />

Poster Panel 40<br />

ID: 3395 - WEPS057<br />

Beam Dynamics Simulation in DTL with RF<br />

Quadrupole Focusing, Sergey Markovich Polozov,<br />

Alexandr Sergeevich Plastun (MEPhI, Moscow) -<br />

There are a number of ion linear accelerators using<br />

RF focusing. Radio Frequency Quadrupole (RFQ) is<br />

the most useful RF linac in low energy range. Using<br />

of RFQ for medium energies is impractical because<br />

of low energy gain rate. Therefore, proposed to<br />

combine Drift Tube Linac (DTL), keeping tolerable<br />

energy gain rate, and RFQ. Such linac consists of<br />

periodic sequence of a several number of drift tubes<br />

and RF quadrupole electrodes, located in the same<br />

IH resonator. Different variants of the structure will<br />

be considered. Beam dynamics simulation will be<br />

carried out through these variants. Main parameters<br />

of the linac will be determine. The RF model design,<br />

providing combination of DTL and RFQ, will be<br />

proposed.<br />

Sub Classification: A08 Linear <strong>Accelerator</strong>s<br />

�<br />

12<br />

Poster Panel 41<br />

ID: 2988 - WEPS045<br />

Feasibility Study of a High-gradient Linac for<br />

Hadrontherapy, Silvia Verdú-Andrés (IFIC,<br />

Valencia; TERA, Novara), Piero Antonio Posocco<br />

(CERN, Geneva), Alberto Degiovanni (EPFL,<br />

Lausanne; TERA, Novara), Angeles Faus-Golfe<br />

(IFIC, Valencia), Ugo Amaldi (TERA, Novara) -<br />

Compact, reliable and little consuming accelerators<br />

are needed for tumor treatment with hadrons. As<br />

solution, TERA proposes CABOTO (CArbon<br />

BOoster for Therapy in Oncology), a linac which<br />

boosts the energy of carbon ions and H_{2}<br />

molecules coming from a cyclotron. The linac,<br />

typically a Side-Coupled Linac (SCL), is divided<br />

into several modules. The beam energy can be<br />

varied in steps of about 15 MeV/u without using<br />

absorbers by acting on the power (amplitude and/or<br />

phase) that feeds the different modules of the linac.<br />

This work presents the structure design of a 5.7 GHz<br />

high repetition rate SCL for a cyclinac, that<br />

accelerates carbon ions from 150 up to 400 MeV/u<br />

in less than 25 meters. The beam dynamics for this<br />

linac and its particular energy selection system is<br />

also discussed for different beam energy outputs.<br />

Funding Agency The research leading to this<br />

results has been funded by the Seventh Framework<br />

Program [FP7/2007-2013] under grant agreement<br />

number 215840-2.<br />

Sub Classification A08 Linear <strong>Accelerator</strong>s<br />

Poster Panel 42<br />

ID: 2646 - THPS001<br />

Experimental Studies of Beam Loss during Low<br />

Energy Operation with Electron Cooled Heavy<br />

Ions in the ESR, Paul Andreas Görgen, Sabrina<br />

Appel, Oliver Boine-Frankenheim (TEMF, TU<br />

Darmstadt, Darmstadt), Oleksandr Chorniy,<br />

Christina Dimopoulou, Tino Giacomini, Stefan<br />

Paret, Markus Steck (GSI, Darmstadt) - At the ESR<br />

at GSI electron cooled heavy ion beams are<br />

decelerated to 4 MeV/u and extracted for the<br />

HITRAP experiment. We will report about cooling<br />

equilibrium measurements at 4 and 30 MeV/u for<br />

Ar18+ coasting beams. We compare the equilibrium<br />

beam parameters with results from beam dynamics<br />

simulations using the BETACOOL code and an<br />

analytic model of reduced complexity. The time slot<br />

in which HITRAP accepts beam is 2μs long. For<br />

optimum efficiency the beam has to be bunched to<br />

this length before extraction. The obtained bunch<br />

profiles are compared to longitudinal beam<br />

dynamics simulations. Our measurements show that


at both energies bunching leads to severe beam loss.<br />

The estimated transverse space charge tune shifts<br />

during the rf bunching indicate that resonance<br />

crossing might be responsible for the observed the<br />

beam loss. The influence of the tune shift will be<br />

further evaluated through resonance measurements.<br />

Sub Classification: A11 Beam Cooling<br />

Poster Panel 43<br />

ID: 3291 - WEPS080<br />

Magnet Design and <strong>Particle</strong> Tracking of Helium<br />

Ion FFAG <strong>Accelerator</strong>, Huanli Luo<br />

(USTC/NSRL, Hefei, Anhui) - As helium ion<br />

source, the periodic focusing structure model of<br />

Helium ion (He+) FFAG (Fixed-Field Alternating<br />

Gradient) accelerator was designed, providing He+<br />

beam with higher beam current at a lower cost,<br />

which could be used for the study of the impact of<br />

Helium embitterment on fusion reactor envelope<br />

material. A radial sector scaling FFAG accelerator<br />

type with eight super-periods and a conventional<br />

magnetic lattice structure, a triplet focusing lattice-<br />

DFD combination, is adopted for He+ FFAG<br />

accelerator. In this paper, magnetic lattice is<br />

optimizing by analytical and numerical techniques.<br />

A large-aperture magnet is designed by using a 3D<br />

magnetic field simulation code OPERA-3D. Runge-<br />

Kutta tracking code used specifically for FFAG<br />

accelerator based on MATLAB language was used<br />

to track the particle in the magnetic field generated<br />

by OPERA-3D, followed by linear and nonlinear<br />

beam dynamics study. Some results of magnet<br />

design, particle tracking and dynamics study are<br />

presented in the article.<br />

Sub Classification: A12 FFAG, Cyclotrons<br />

Poster Panel 44<br />

ID: 2030 - WEPS098<br />

Combined Momentum Collimation Method in<br />

High-intensity Rapid Cycling Proton<br />

Synchrotrons, Jin-Fang Chen, Jingyu Tang, Ye<br />

Zou (IHEP Beijing, Beijing) - A new momentum<br />

collimation method – so-called combined<br />

momentum collimation method in high-intensity<br />

synchrotrons is proposed and studied here, which<br />

makes use two-stage collimation in both the<br />

longitudinal and the transverse phase planes. The<br />

primary collimator is placed at a high-dispersion<br />

location of an arc, and the longitudinal and<br />

transverse secondary collimators are in the same arc<br />

and in the down-stream dispersion-free long straight<br />

section, respectively. The particles with positive<br />

momentum deviations will be scattered and<br />

�<br />

13<br />

degraded by a carbon scraper and then cleaned<br />

mainly by the transverse collimators, whereas the<br />

particles with negative momentum deviations will be<br />

scattered by a tantalum scraper and mainly cleaned<br />

by the longitudinal secondary collimators in the<br />

successive turns. Numerical simulation results using<br />

TURTLE and ORBIT codes show that this method<br />

gives high collimation efficiency for medium-energy<br />

synchrotrons. The studies have also shown two<br />

interesting effects: one is that the momentum<br />

collimation is strongly dependent on the transverse<br />

beam correlation; the other is that the material for<br />

the primary collimator plays an important role in the<br />

method.<br />

This work was supported by the National Natural<br />

Science Foundation of China (10975150,<br />

10775153), the CAS Knowledge Innovation<br />

Program-“CSNS R&D Studies”. Funding Agency<br />

Sub Classification: A15 High Intensity<br />

<strong>Accelerator</strong>s<br />

Poster Panel 45<br />

ID: 2909 - THPS021<br />

Methods to Obtain High Intensity Proton Ion<br />

Beams with Low Emittance from ECR Ion<br />

Source at Peking University, Haitao Ren<br />

(Graduate University, Beijing), Zhiyu Guo,<br />

Pengnan Lu, Shi Xiang Peng, Zhi Zhong Song, Jin<br />

Xiang Yu, Meng Zhang, Jie Zhao, Quanfeng Zhou<br />

(PKU/IHIP, Beijing), Jia-er Chen (PKU/IHIP,<br />

Beijing; NSFC, Beijing) - With the development of<br />

accelerator technology, to obtain an ion beam with<br />

high intensity and low emittance is becoming one of<br />

the main goals of research for ion sources. At Peking<br />

University we have developed several 2.45 GHz<br />

electron cyclotron resonance (ECR) ion sources for<br />

different projects and we paid close attention to the<br />

beam intensity increasing as well as the beam<br />

emittance reduction. Methods are adopted to<br />

improve beam intensity by increasing the density of<br />

plasma inside the discharge chamber, optimizing the<br />

geometry pinch effect and the perveance at the<br />

extraction aperture. To suppress the emmitance<br />

increasing of an extracted beam, the shape of the<br />

electrodes as well as the voltage of suppression<br />

electrode are carefully selected With these efforts, a<br />

120 mA total proton beam has been extracted from<br />

the permanent magnet ECR ion source at 50 kV, and<br />

the measured normalized rms emittance is less than<br />

0.2 pi.mm.mrad. The beam current density at the<br />

extraction aperture is about 420 mA/cm2.<br />

Sub Classification: T01 Proton and Ion Sources


Poster Panel 46<br />

ID: 1786 - THPS033<br />

Skew Quadrupole Effects on Multi-turn injection<br />

Efficiency in SIS18, Wafa Mahmood Daqa,<br />

Ingo Hofmann, Jurgen Struckmeier (GSI,<br />

Darmstadt) - One goal of the SIS18 upgrade scheme<br />

is concerned about improving the multi-turn<br />

injection (MTI) efficiency, in order to reach the<br />

required intensities at the targets and to operate<br />

effectively as a booster for SIS100. To improve the<br />

limitation of the MTI scheme, there were successful<br />

attempts in AGS and PS boosters, to use the skew<br />

injection scheme and later it was suggested for<br />

SIS18. The strength of the skew quadrupoles is<br />

optimized together with the horizontal tune, the<br />

difference in horizontal to vertical tunes, the<br />

�<br />

14<br />

incoming beam parameters and the geometrical<br />

limitation of SIS lattice. A good optimization<br />

implies the emittance exchange, due to linear<br />

coupling, to take place partially and just before the<br />

return of the beamlet back to its original position at<br />

the septum. The present work was done by<br />

simulation using the code PARMTRA and compared<br />

with measurements. The results show that,<br />

depending on the working point, the skew injection<br />

scheme can improve the MTI efficiency from 5% up<br />

to 15%, taking into account the loss on the septum<br />

from inside and on the vertical acceptance.<br />

Funding Agency DAAD ( Deutscher Akademischer<br />

Austausch Dienst)<br />

Sub Classification: T12 Beam Injection/Extraction<br />

and Transport


�<br />

Classification 5: Beam Dynamics and Electromagnetic Fields<br />

Poster Panel 47<br />

ID: 3546 - WEPC036<br />

Coherent Synchrotron Radiation Source Based<br />

on an Isochronous Accumulator Ring with<br />

Femtosecond Electron Bunches, Nuan-Ya Huang<br />

(NTHU, Hsinchu), Wai Keung Lau (NSRRC,<br />

Hsinchu), Hiroyuki Hama, Fujio Hinode, Shigeru<br />

Kashiwagi, Masayuki Kawai, Fusashi Miyahara,<br />

Toshiya Muto, Ken-ichi Nanbu, Yuu Tanaka<br />

(Tohoku University, Sendai) - A compact<br />

isochronous accumulator ring has been studied as a<br />

source of coherent synchrotron radiation (CSR) at a<br />

wavelength region from THz to GHz. Since the<br />

thermionic rf gun is substantially stable in general,<br />

we anticipate a bunch train of very short electron<br />

pulses can be provided satisfactorily by means of<br />

velocity bunching. Careful numerical simulations<br />

show possibility of the bunch length of much less<br />

than 100 fs with a bunch charge of 20 pC, which<br />

will contain sufficiently large form factor for<br />

production of CSR at the wavelengths longer than ~<br />

0.1 mm. The coherent THz radiation of high average<br />

power will be achieved if the short bunches can be<br />

circulated in the accumulator ring without bunch<br />

lengthening. This paper will describe the<br />

optimization of thermionic injector to produce<br />

femtosecond bunches in addition to study of the<br />

lattice designing of complete isochronous optics for<br />

the accumulator ring.<br />

Sub Classification: D01 Beam Optics - Lattices,<br />

Correction Schemes, Transport<br />

Poster Panel 48<br />

ID: 3082 - WEPC009<br />

Design of an Antiproton Injection and Matching<br />

Beam Line for the AD Recycler Ring,<br />

Oleg Karamyshev, Galina Karamysheva, Alexander<br />

Ivanovich Papash (JINR, Dubna, Moscow Region;<br />

MPI-K, Heidelberg), Michele Ruth Fisher Siggel-<br />

King, Carsten Peter Welsch (Cockcroft Institute,<br />

Warrington, Cheshire; The University of Liverpool,<br />

Liverpool) - A small antiproton recycler ring (AD-<br />

Rec) for use in the MUSASHI beamline at the<br />

CERN AD has been designed by the QUASAR<br />

Group for operation at energies between 3 and 30<br />

keV. A highly efficient beam line for capturing the<br />

beam after extraction from the trap, transporting and<br />

injecting it into the AD Rec is very important to<br />

minimize losses and full the ring up to its space<br />

charge limit. In this contribution, the beam optical<br />

15<br />

and mechanical design of the injector is presented.<br />

Funding Agency: Work supported by STFC, the<br />

Helmholtz Association and GSI under contract VH-<br />

NG.328.<br />

Sub Classification: D01 Beam Optics - Lattices,<br />

Correction Schemes, Transport<br />

Poster Panel 49<br />

ID: 4135 - WEPC006<br />

Upgrade Plans on the Superconducting Electron<br />

<strong>Accelerator</strong> S-DALINAC, Michaela Kleinmann,<br />

Ralf Eichhorn, Florian Hug, Norbert Pietralla (TU<br />

Darmstadt, Darmstadt) - The S-DALINAC is a<br />

superconducting recirculating electron accelerator<br />

with maximum design energy of 130 MeV operating<br />

in cw at 3 GHz. Even so the gradients of the<br />

superconducting cavities are well above design, their<br />

design quality factor of 3*10^9 have not been<br />

reached so far, leading to higher heat transfer into<br />

the liquid helium than expected. Due to the limited<br />

cooling power of the cryo-plant being 120 W, the<br />

final energy achievable in cw operation is around 85<br />

MeV, currently. In order to provide a cw beam with<br />

the designed final energy in the future, the<br />

installation of an additional recirculation path is<br />

projected. We will report on the beam-line and the<br />

magnet design for the new recirculation path. In<br />

addition, we will present the layout of two proposed<br />

scraper-systems which will be used to remove the<br />

halo of the electron beam allowing high precision<br />

coincidence experiments with very low background<br />

for nuclear physics in the future.<br />

Funding Agency: Work supported by DFG through<br />

SFB 634<br />

Sub Classification: D01 Beam Optics - Lattices,<br />

Correction Schemes, Transport<br />

Poster Panel 50<br />

ID: 3347 - WEPC013<br />

Tests for Low Vertical Emittance at Diamond<br />

using LET Algorithm, Simone Maria Liuzzo,<br />

Maria Enrica Biagini, Pantaleo Raimondi<br />

(INFN/LNF, Frascati (Roma)), Riccardo Bartolini<br />

(Diamond, Oxfordshire; JAI, Oxford) - We present<br />

measurements recently performed at the Diamond<br />

Light Source, aimed at the achievement of low<br />

vertical emittance using the Low Emittance Tuning<br />

(LET) algorithm developed for a SuperB factory<br />

project presently in progress. The tests have been<br />

focused on the comparison between this method and


the LOCO algorithm currently used at Diamond.<br />

Beam position monitor tilts estimate and multiple<br />

coupling response matrices have been introduced in<br />

the algorithm in order to optimize the procedure.<br />

After few iterations using vertical correctors and<br />

skew quadrupoles, very low vertical dispersion and<br />

emittance coupling, comparable to those obtained by<br />

LOCO, have been measured.<br />

Sub Classification: D01 Beam Optics - Lattices,<br />

Correction Schemes, Transport<br />

Poster Panel 51<br />

ID: 3643 - WEPC018<br />

C-band Standing-wave Accelerating Structure<br />

with RF Focusing, Hae-Ryong Yang, Moo-Hyun<br />

Cho, Sang-Hoon Kim, Won Namkung, Sung-Ju<br />

Park (POSTECH, Pohang, Kyungbuk), Jong-Seok<br />

Oh (NFRI, Daejon) - In electron RF linacs for<br />

industrial X-ray sources, more compact structure is<br />

preferred for handling capability and mobility. The<br />

beam should be focused for the spot size at a<br />

conversion target to be 1 – 2 mm for these<br />

applications. External focusing magnets are not<br />

necessary by using RF focusing effects. We design a<br />

C-band linac, which is capable of producing 6-MeV,<br />

50-mA pulsed electron beams. It uses a bi-periodic<br />

and on-axis-coupled structure with the built-in<br />

bunching section, and operated with the π/2-mode<br />

standing-waves. In this linac, the bunching cells are<br />

designed for bunched electrons to be focused by RF<br />

focusing effect, in which beam velocity is gradually<br />

accelerated to speed of light. In this paper, we<br />

present the beam dynamics with the PARMELA<br />

simulation. We also discuss the focusing effect by<br />

the ponderomotive force.<br />

Sub Classification: D01 Beam Optics - Lattices,<br />

Correction Schemes, Transport<br />

Poster Panel 52<br />

ID: 3070 - WEPC052<br />

Effect of Compton Scattering on the Electron<br />

Beam Dynamics at the ATF Damping Ring,<br />

Iryna Chaikovska, Christelle Bruni, Nicolas<br />

Delerue, Alessandro Variola, Fabian Zomer (LAL,<br />

Orsay), Kiyoshi Kubo, Takashi Naito, Tsunehiko<br />

Omori, Nobuhiro Terunuma, Junji Urakawa (KEK,<br />

Ibaraki) - Compton scattering provides one of the<br />

most promising scheme to obtain polarized positrons<br />

for the next generation of lepton machines.<br />

Moreover it is an attractive method to produce<br />

monochromatic high energy polarized gammas for<br />

nuclear applications and X-rays for compact light<br />

sources. In this framework a four-mirror Fabry-Perot<br />

�<br />

16<br />

cavity has been installed at the <strong>Accelerator</strong> Test<br />

Facility (ATF - KEK, Tsukuba, Japan) and will be<br />

used to produce an intense flux of polarized gamma<br />

rays by Compton scattering. For electrons at the<br />

energy of the ATF (1.3GeV) Compton scattering<br />

may result in a shorter lifetime due to the bucket<br />

acceptance. We have implemented the effect of<br />

Compton scattering on a 2D tracking code with a<br />

Monte-Carlo method. This code has been used to<br />

study the longitudinal dynamics of the electron<br />

beam at the ATF damping ring, in particular the<br />

evolution of the energy spread and the bunch length<br />

under Compton scattering. The results obtained are<br />

presented and discussed. Possible methods to<br />

observe the effect of Compton scattering on the ATF<br />

beam are proposed.<br />

Sub Classification: D02 Non-linear Dynamics -<br />

Resonances, Tracking, Higher Order<br />

Poster Panel 53<br />

ID: 2890 - WEPC059<br />

Nonlinear Properties of the ESR Magnets and<br />

their Influence on Beam Optics, Oleksii Gorda,<br />

Christina Dimopoulou, Alexei Dolinskii, Sergey<br />

Litvinov, Fritz Nolden, Markus Steck (GSI,<br />

Darmstadt) - The Experimental Storage Ring (ESR)<br />

at GSI is operated for accumulation and cooling of<br />

heavy ion beams in the energy range of 4-400<br />

MeV/u. Recent results of machine experiments<br />

demonstrated that the ring acceptance is strongly<br />

restricted by nonlinear field contributions. Higherorder<br />

field harmonics of the dipole and quadrupole<br />

magnets were calculated and used in particle<br />

tracking simulations in order to understand the<br />

sources of the acceptance limitations. To benchmark<br />

the results of numerical calculations, chromaticity<br />

measurements were performed with a uranium beam<br />

at the energy of 400 MeV/u. Results of magnetic<br />

field simulations for the ESR magnets and a<br />

comparison between measured and calculated<br />

chromaticity of the ring will be presented.<br />

Sub Classification: D02 Non-linear Dynamics -<br />

Resonances, Tracking, Higher Order<br />

Poster Panel 54<br />

ID: 4031 - WEPC082<br />

Linear Coherent Beam-Beam Parameter and<br />

Beam-beam Induced Orbit Effects at LHC,<br />

Michaela Schaumann, Reyes Alemany-Fernandez,<br />

Werner Herr (CERN, Geneva) - The study of the<br />

Linear Coherent Beam-Beam Parameter at LHC has<br />

been determined with head-on collisions with small<br />

number of bunches. Two different energies have


een probed, the injection energy (450 GeV) and the<br />

collision energy (3.5 TeV). The results obtained are<br />

presented. For high LHC bunch intensities the<br />

Beam-Beam force is strong enough to expect orbit<br />

effects if the two beams do not collide head-on but<br />

with a crossing angle. As a consequence the closed<br />

orbit changes. The closed orbit of an unperturbed<br />

machine with respect to a machine where the Beam-<br />

Beam force become more and more important has<br />

been studied and the results are presented.<br />

Sub Classification: D02 Non-linear Dynamics -<br />

Resonances, Tracking, Higher Order<br />

Poster Panel 55<br />

ID: 3038 - WEPC068<br />

The Spin Aberration of Polarized Beam in the<br />

Electrostatic Ring, Yurij Senichev, Rudolf Maier,<br />

Denis Zyuzin (FZJ, Jülich) - Analytical solution for<br />

components of the spin vector is recorded in the<br />

form of transform matrixes for different electrostatic<br />

elements. These matrixes are used for numerical<br />

simulation of spin motion in the electrostatic ring for<br />

arbitrary particle in a similar way to phase motion.<br />

By this method we investigate behaviour of spin at<br />

different initial spin orientation and different beam<br />

energy. For a beam with nonzero transverse<br />

emittance at particle passage through a non-uniform<br />

electric field, for example an electric focusing lens,<br />

the orientation of a spin vector becomes function of<br />

phase variables that leads to the spin aberration. We<br />

investigate this process analytically and numerically.<br />

Sub Classification D02 Non-linear Dynamics -<br />

Resonances, Tracking, Higher Order<br />

Poster Panel 56<br />

ID: 3778 - MOPS029<br />

Experiments with a Fast Chopper System for<br />

Intense Ion Beams, Hannes Dinter, Martin Droba,<br />

Marcel Lotz, Oliver Meusel, Ilja Mueller, Daniel<br />

Noll, Ulrich Ratzinger, Kathrin Schulte, Christopher<br />

Wagner, Christoph Wiesner (IAP, Frankfurt am<br />

Main) - Chopper systems are used to pulse charged<br />

particle beams. In most cases, electric deflection<br />

systems are used to generate beam pulses of defined<br />

lengths and appropriate repetition rates. At high<br />

beam intensities, the field distribution of the chopper<br />

system needs to be adapted precisely to the beam<br />

dynamics in order to avoid aberrations. An<br />

additional challenge is a robust design which<br />

guarantees reliable operation. For the Frankfurt<br />

Neutron Source FRANZ, an E×B chopper system is<br />

being developed which combines static magnetic<br />

deflection with a pulsed electric field in a Wien filter<br />

�<br />

17<br />

configuration. It will generate proton pulses with a<br />

flat top of 50 ns at a repetition rate of 250 kHz for<br />

120 keV, 200 mA beams. For the electric deflection,<br />

pre-experiments with static and pulsed fields were<br />

performed using a helium ion beam. In pulsed mode<br />

operation, ion beams of different energies were<br />

deflected with voltages of up to ±6 kV and the<br />

resulting response was measured using a beam<br />

current transformer. A comparison between<br />

experiments and theoretical calculations as well as<br />

numerical simulations are presented.<br />

Sub Classification: D04 High Intensity in Linear<br />

<strong>Accelerator</strong>s<br />

Poster Panel 57<br />

ID: 2706 - MOPS034<br />

Progress on Space Charge Compensation Study<br />

in Low Energy High Intense H+ Beam,<br />

Pengnan Lu, Zhiyu Guo, Shi Xiang Peng, Zhi<br />

Zhong Song, Jin Xiang Yu, Zhong Xi Yuan, Jie<br />

Zhao (PKU/IHIP, Beijing), YingJun Ma (CIAE,<br />

Beijing), Haitao Ren (Graduate University, Beijing)<br />

- This article draws emphasis on the correlation<br />

between the space charge compensation (SCC) and<br />

the beam quality in different operation conditions.<br />

Theoretical improvement has been made to the<br />

model of <strong>Particle</strong> Life Span � PLS � which was<br />

developed in Peking University. In the improved<br />

model the thermal motion of electrons is considered<br />

with relaxed assumptions. And more detailed<br />

boundary conditions are used in calculating particle<br />

distribution. Based on the theoretical analysis three<br />

series of experiments have been conducted. Firstly,<br />

transport efficiency beam intensity, beam profile and<br />

emittance variation are quantitatively studied<br />

together with energy spectra of Compensation Gas<br />

Ions (CGI) in 50KeV/100mA H+ beam. Secondly,<br />

to explore better SCC efficiency we tested the<br />

function of ring electrodes in inhibiting electron<br />

escape. Moreover both Ar and Kr were used as<br />

comparison of different compensation gas. Lastly,<br />

SCC with pure additional electrons from a<br />

transverse electron gun is preliminarily<br />

experimented. All results will be presented and<br />

discussed in the text for seeking the best<br />

circumstances in SCC dominated low energy high<br />

intensity ion beams.<br />

Sub Classification: D04 High Intensity in Linear<br />

<strong>Accelerator</strong>s


Poster Panel 58<br />

ID: 3631 - MOPS030<br />

Beam Dynamics of the FRANZ Bunch<br />

Compressor using Realistic Fields with a Focus<br />

on the Rebuncher Cavities, Daniel Noll, Long Phi<br />

Chau, Martin Droba, Oliver Meusel, Holger<br />

Podlech, Ulrich Ratzinger, Christoph Wiesner (IAP,<br />

Frankfurt am Main) - The ARMADILLO bunch<br />

compressor currently being designed at IAP is<br />

capable of reaching a longitudinal pulse<br />

compression ratio of 45 for proton beams of 150 mA<br />

at 2 MeV. It will provide one nanosecond proton<br />

pulses with a peak current of 7.7 A. The system<br />

guides nine linac micro bunches deflected by a 5<br />

MHz rf kicker and uses four dipole magnets - two<br />

homogeneous and two with field gradients - to<br />

merge them on the target. For longitudinal focusing<br />

and an energy variation of ±200 keV two multitrack<br />

rf cavities are included. ARMADILLO will be<br />

installed at the end of the Frankfurt Neutron Source<br />

FRANZ making use of the unique 250 kHz time<br />

structure. This contribution will provide an overview<br />

of the layout of the system as well as recent<br />

advances in component design and beam dynamics<br />

of the compressor.<br />

Funding Agency: Work supported by HIC for FAIR.<br />

Sub Classification: D04 High Intensity in Linear<br />

<strong>Accelerator</strong>s<br />

Poster Panel 59<br />

ID: 3745 - MOPS038<br />

3D Beam Dynamic Simulation in Heavy Ion<br />

Superconducting Drift Tube Linac,<br />

Alexandr Vyacheslavovich Samoshin, Sergey<br />

Markovich Polozov (MEPhI, Moscow) - The<br />

superconducting (SC) linac conventionally consists<br />

of some different classes of the identical cavities.<br />

Each cavity is based on a SC structure with a high<br />

accelerating gradient. The low charge state beams<br />

require stronger transverse focusing. This focusing<br />

can be reached with the help of SC solenoid lenses.<br />

In this paper beam dynamics simulation obtain by<br />

smooth approximation and full field. Traditionally<br />

only the Coulomb field is taken into account for low<br />

energy beams. In this paper the computer simulation<br />

of heavy ion beam dynamics in superconducting<br />

(SC) linac will carried out by means of the "particlein-cell"<br />

method. Simulation results will present.<br />

Sub Classification: D04 High Intensity in Linear<br />

<strong>Accelerator</strong>s<br />

Poster Panels 60 and 61 are manned by<br />

Sanghoon Kim because Moonsik Chae’s travel<br />

�<br />

18<br />

arrangements do not allow him to be in San<br />

Sebastian in time.<br />

Moonsik Chae’s work cannot be considered for<br />

the best poster prize.<br />

Poster Panel 60<br />

ID: 3352 - MOPS035<br />

Energy Spreads by Transient Beam Loading<br />

Effect in Pulsed RF Linac, Sang-Hoon Kim, Moo-<br />

Hyun Cho, Hae-Ryong Yang (POSTECH, Pohang,<br />

Kyungbuk), Jong-Seok Oh (NFRI, Daejon), Won<br />

Namkung (PAL, Pohang, Kyungbuk) - RF linacs for<br />

high power beams are operated in the fully beamloaded<br />

condition for the power efficiency. In this<br />

condition, temporal energy spreads are induced by<br />

the transient beam loading effect. Irradiation sources<br />

require the beam energy of less than 10 MeV to<br />

prevent undesirable neutron production. In order to<br />

maximize the beam power and maintain the beam<br />

energy in a safe value, we need to suppress the<br />

temporal energy spreads. In an L-band travelingwave<br />

linac for irradiation sources, the high energy<br />

electrons are suppressed by the beam current<br />

modulation with the RF power modulation. As a<br />

result, the average beam energy and the<br />

corresponding beam power are improved by nearly<br />

60% compared to the case without any modulations.<br />

Funding Agency Work partly supported by<br />

KAPRA and POSTECH Physics BK21 Program<br />

Sub Classification: D04 High Intensity in Linear<br />

<strong>Accelerator</strong>s<br />

Poster Panel 61<br />

Main Classification: 07 <strong>Accelerator</strong> Technology<br />

Sub Classification: T06 Room Temperature RF<br />

ID: 3599 - MOPC033<br />

The Status of a 1.6-cell Photocathode RF Gun at<br />

PAL, MoonSik Chae, Juho Hong, In Soo Ko, Yong<br />

Woon Parc (POSTECH, Pohang, Kyungbuk),<br />

Changbum Kim, Sung-Ju Park (PAL, Pohang,<br />

Kyungbuk) - The high power beam test of the<br />

photocathode RF gun with four holes at the side of<br />

the full cell which is fabricated at PAL has been<br />

finished. With the gun test stand which consists of a<br />

1.6 cell cavity, a solenoid magnet, beam diagnostic<br />

components and auxiliary systems such as ICT,<br />

spectrometer, YAG scintillator and screens, Faraday<br />

cup, etc. Basic diagnostics such as the measurements<br />

of charge, energy and its spread, transverse<br />

emittance has been performed and it confirms a<br />

successful fabrication of the RF gun. Here we<br />

present the process of the beam test and the results


of measurements on various beam parameters.<br />

Comparison of the results between the measurement<br />

and the simulation is also presented.<br />

Poster Panel 62<br />

ID: 3909 - MOPS023<br />

An Analytical Lagragian Model for Analyzing<br />

Temperature Effects in Intense Non-neutral<br />

Beams, Everton Granemann Souza, Antonio<br />

Endler, Renato Pakter, Felipe Barbedo Rizzato (IF-<br />

UFRGS, Porto Alegre) - High-intensity chargedparticle<br />

beams are used in several areas of physics.<br />

We can mention as an illustration, high-energy<br />

colliders, particle accelerators and vacuum electron<br />

devices. In all cases quoted above, the beam lose<br />

particles in the acceleration process, between its<br />

production to its final destination. These ejected<br />

particles, generally, produce a surrounding structure<br />

around the beam core, called halo. This undesirable<br />

structure is seen in simulation as well as in actual<br />

linacs, and its formation has been one of the main<br />

sources of energy loss in the acceleration devices.<br />

For this reason, the need for an advance in<br />

understand the mechanism that produce the halo<br />

becomes necessary. In view of the whole problem,<br />

we contruct a 1D Lagrangian warm-fluid model for<br />

describe the behavior of inhomogeneous chargedparticle<br />

beam in solenoidal focusing magnetic field.<br />

The equations of motion are derived for an adiabatic<br />

process with a state equation originated from the<br />

ideal gas law. In the end, the model is compared<br />

with self-consistent simulation and is used to explain<br />

emittance growth and jets of particle, even when the<br />

system is out of equilibrium.<br />

Sub Classification: D04 High Intensity in Linear<br />

<strong>Accelerator</strong>s<br />

Poster Panel 63<br />

ID: 4117 - MOPS010<br />

Experimental Studies with Low Transition<br />

Energy Optics in the SPS, Hannes Bartosik,<br />

Theodoros Argyropoulos, Thomas Bohl, Stephane<br />

Cettour Cave, Karel Cornelis, Yannis<br />

Papaphilippou, Giovanni Rumolo, Benoit Salvant,<br />

Elena Shaposhnikova, Jorg Wenninger (CERN,<br />

Geneva) - The optics of the SPS can be tuned to<br />

lower transition energy such that the slippage factor<br />

at injection is raised by a factor of almost 3. From<br />

theory, an increase of the intensity thresholds for<br />

transverse mode coupling instabilities, longitudinal<br />

coupled bunch instabilities and longitudinal<br />

instabilities due to the loss of Landau damping can<br />

be expected. In this paper, experimental studies with<br />

�<br />

19<br />

LHC-type proton beams in the SPS with very high<br />

intensities of up to 3.5e11 p/b on the flat bottom and<br />

at 450 GeV/c are presented. In particular, the<br />

measurements address the increase of intensity<br />

thresholds and the achievable transverse emittances<br />

in the new low gamma transition optics with respect<br />

to the nominal SPS optics. The obtained results are<br />

compared with numerical simulations.<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 64<br />

ID: 3000 - MOPS078<br />

Coaxial Wire Simulations of Ferrite Kicker<br />

Magnets, Hugo Alistair Day (CERN, Geneva;<br />

UMAN, Manchester), Michael John Barnes, Fritz<br />

Caspers, Elias Métral, Benoit Salvant, Carlo Zannini<br />

(CERN, Geneva), Roger Michael Jones (UMAN,<br />

Manchester) - Fast kicker magnets are used to inject<br />

beam into and eject beam out of the CERN<br />

accelerator rings. These kickers are generally<br />

transmission line type magnets with a rectangular<br />

shaped aperture through which the beam passes.<br />

Unless special precautions are taken the impedance<br />

of the yoke can provoke significant beam induced<br />

heating, especially for high intensities. In addition<br />

the impedance can contribute to beam instabilities.<br />

The results of longitudinal and transverse impedance<br />

measurements, for various kicker magnets, are<br />

presented and compared with analytical calculations:<br />

in addition predictions from a numerical analysis are<br />

discussed.<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 65<br />

ID: 4127 - MOPS060<br />

Simulation of Resistive Wall Instabilities in<br />

CSNS/RCS, Liangsheng Huang (IHEP Beijing,<br />

Beijing) - Rapid Cycling Synchrotron (RCS�of The<br />

China Spallation Neutron Source (CSNS) is a high<br />

intensity proton accelerator, with average beam<br />

power of 100kW. The collective effects caused by<br />

the coupling impedance may be the limit to beam<br />

power. Based on the impedance estimation for<br />

components on beam line, the resistive wall<br />

impedance and its instability are more serious than<br />

any other instability. In this paper, a simple resistive<br />

wall wake field model is used to simulate the bunch<br />

oscillation and instability growth rate. In this model,<br />

the continuous resistive wall wake field is equivalent<br />

to points wake field along the RCS, and long bunch<br />

is sliced into many micro-bunches. By tracking the


dynamics of the micro-bunches, the transverse<br />

growth rate and beam size blow-up were obtained.<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 66<br />

ID: 4119 - MOPS075<br />

Simulation of Multibunch Motion with the<br />

HEADTAIL Code and Application to the SPS<br />

and the LHC, Nicolas Mounet (CERN, Geneva;<br />

EPFL, Lausanne), Elias Métral, Giovanni Rumolo<br />

(CERN, Geneva) - Multibunch instabilities due to<br />

beam-coupling impedance can be a critical<br />

limitation for synchrotrons operating with many<br />

bunches. It is particularly true for the LHC under<br />

nominal conditions, where according to theoretical<br />

predictions the 2808 bunches rely entirely on the<br />

performance of the transverse feedback system to<br />

remain stable. To study these instabilities, the<br />

HEADTAIL code has been extended to simulate the<br />

motion of many bunches under the action of wake<br />

fields. All the features already present in the singlebunch<br />

version of the code, such as synchrotron<br />

motion, chromaticity, amplitude detuning due to<br />

octupoles and the ability to load any kind of wake<br />

fields through tables, have remained available. This<br />

new code has been then parallelized in order to track<br />

thousands of bunches in a reasonable amount of<br />

time. The code was benchmarked against theory and<br />

exhibited a good agreement. We also show results<br />

for bunch trains in the SPS and compare them with<br />

beam-based measurements.<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 67<br />

ID: 2927 - MOPS052<br />

Analytical and Numerical Calculations of Beam<br />

Pipe Impedances at Low Frequencies with<br />

Application to the Thin SIS100 Pipe,<br />

Uwe Niedermayer, Oliver Boine-Frankenheim,<br />

Lukas Haenichen (TEMF, TU Darmstadt,<br />

Darmstadt) - The projected fast ramped synchrotron<br />

SIS100 for FAIR uses an elliptical stainless steel<br />

beam pipe of 0.3 mm thickness. The lowest coherent<br />

betatron sidebands reach down to 100 kHz which<br />

demands accurate impedance calculations in the low<br />

frequency (LF) regime. For these frequencies, i.e.<br />

skin depth greater than wall thickness, structures<br />

behind the pipe may contribute to the impedance.<br />

Due to the extremely large wake length numerical<br />

methods in the time domain are not applicable. The<br />

longitudinal and transverse impedance of the thin<br />

�<br />

20<br />

SIS100 beam pipe including structures behind the<br />

pipe are obtained numerically by a method using<br />

power loss in the frequency domain. We compare<br />

different analytical models for simplified pipe<br />

structures to the numerical results. The dc and ultrarelativistic<br />

limits are investigated. The interpretation<br />

of bench measurements in the LF regime is<br />

discussed.<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 68<br />

ID: 3691 - MOPS054<br />

Impedance of the Kicker Power Supply for the<br />

SIS100 Synchrotron, Katarina Samuelsson,<br />

Volker Hinrichsen (TU Darmstadt, Darmstadt), Udo<br />

Blell, Jürgen Florenkowski, Isfried Josef<br />

Petzenhauser, Peter J. Spiller (GSI, Darmstadt) -<br />

SIS100 will be operated with high intensity heavyion<br />

and proton beams. The reduction of ring<br />

impedances is therefore of great importance in order<br />

to avoid coherent beam instabilities. The kicker<br />

system is one of the main contributors to the overall<br />

ring impedance in SIS100. This paper will focus on<br />

the contribution of the external network to the kicker<br />

impedance. Calculations as well as experimental<br />

impedance measurements of the network<br />

contribution have already been carried out for the<br />

SIS18 and ESR kickers. The SIS100 will be<br />

equipped with a bipolar kicker system, which uses a<br />

Pulse Forming Network (PFN) as energy storage.<br />

For potential detachment purposes an insulation<br />

transformer will be installed. Since this setup is new<br />

in several ways it is important to know its<br />

contribution to the coupling impedance of the kicker<br />

system. In this contribution the corresponding<br />

numerical calculation is presented.<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 69<br />

ID: 4528 - MOPS089<br />

Identification of Bunch Dynamics in the Presence<br />

of E-Cloud and TMCI for the CERN SPS Ring,<br />

Ozhan Turgut, John Fox, Claudio Hector Rivetta<br />

(SLAC, Menlo Park, California) - Measurements<br />

and multi-particle simulation codes (i.e. HEAD-<br />

TAIL, WARP, CMAD) indicate that bunched<br />

particle beams show unstable motions induced by<br />

electron-clouds and strong head-tail interactions.<br />

The bunch dynamics exhibits highly non-linear,<br />

complex and unstable behavior under certain<br />

operating conditions. Feedback control systems have


een proposed to mitigate these instabilities in the<br />

CERN SPS ring. The design of feedback systems<br />

requires the knowledge of a reduced dynamic model<br />

of the bunch. It allows to include and quantify the<br />

effect of noise and signal perturbations, as well as<br />

system robustness to parameter variation.<br />

Identification techniques are used to estimate those<br />

models based on bunch motion measurements. In<br />

this work we present reduced mathematical models<br />

representing the transverse bunch dynamics and<br />

identification techniques to extract the model<br />

parameters based on measurements. These<br />

techniques are validated using time domain<br />

simulations of the bunch motion conducted using<br />

multi-particle simulation codes. For that, different<br />

sections of the bunch are driven by random signals,<br />

and the vertical motion of those areas is used to<br />

estimate the reduced model.<br />

Funding Agency: Work is supported by the U.S.<br />

Department of Energy under contract DE-AC02-<br />

76SF00515 and the US LHC <strong>Accelerator</strong> Research<br />

Program (LARP).<br />

Sub Classification: D05 Instabilities - Processes,<br />

Impedances, Countermeasures<br />

Poster Panel 70<br />

ID: 3186 - TUOAB03<br />

Enlarging Dynamic and Momentum Aperture by<br />

<strong>Particle</strong> Swarm Optimization, Zhenghe Bai, Weimin<br />

Li, Lin Wang (USTC/NSRL, Hefei, Anhui) -<br />

<strong>Particle</strong> swarm optimization (PSO) is a<br />

computational intelligence algorithm for global<br />

optimization. Obtaining adequate dynamic and<br />

momentum aperture is crucial for high injection<br />

efficiency and long beam lifetime in low emittance<br />

electron storage rings. Different from nonlinear<br />

driving terms optimization, we have made direct<br />

optimization of dynamic and momentum aperture by<br />

PSO algorithm. It is critical to make a criterion for<br />

comparison of dynamic and momentum aperture<br />

tracking results in the direct optimization procedure.<br />

Thus, in this paper we first propose a quantitative<br />

criterion of dynamic aperture. Then we apply PSO<br />

to the optimization of chromatic and harmonic<br />

sextupoles to find the optimum sextupole settings<br />

for enlarging the dynamic aperture. Taking the<br />

momentum aperture into consideration, we make<br />

joint optimization of dynamic and momentum<br />

aperture. Also, the momentum aperture has its<br />

quantitative criterion. As an example of application,<br />

the dynamic and momentum aperture of an FBA<br />

lattice studied in the design of storage ring of Hefei<br />

�<br />

21<br />

Advanced Light Source were optimized, and the<br />

results have shown the power of PSO algorithm.<br />

Sub Classification: D06 Code Developments and<br />

Simulation Techniques<br />

Poster Panel 71<br />

ID: 3144 - WEPC097<br />

Calculation of High Frequency Fields in<br />

Resonant Cavities Based on Perturbation Theory,<br />

Korinna Brackebusch, Hans-Walter Glock, Ursula<br />

van Rienen (Rostock University, Rostock) - The<br />

knowledge of the eigenmodes of resonant<br />

accelerator cavities is essential for the determination<br />

of their performance characteristics, comprising<br />

resonant frequencies and field distributions inside<br />

the cavities. Apart from the material properties the<br />

eigenmodes of a cavity depend on its geometry. In<br />

spite of the high elaborateness during the complex<br />

fabrication process, minor deviations of the actual<br />

cavity shape from the desired one are inevitable.<br />

Moreover, especially superconducting cavities are<br />

subject to extreme operating conditions that may<br />

cause deformations of their shape. Any geometry<br />

perturbation results in a shift of the resonant<br />

frequencies and modified field distributions. In this<br />

paper, we will analyze a generalization of Slater's<br />

theorem proposed in literature. The method should<br />

allow for the calculation of resonant frequencies and<br />

field distributions of a slightly perturbed cavity by<br />

using a set of precomputed eigenmodes of the<br />

unperturbed cavity. We will evaluate the<br />

practicability of the method by applying it to cavity<br />

geometries for which the eigenmodes are<br />

analytically known, ascertain the effort of<br />

reasonable calculation results and describe its<br />

limitations.<br />

Funding Agency: Work supported by Federal<br />

Ministry for Research and Education BMBF under<br />

contracts 05H09HR5 and 05K10HRC.<br />

Sub Classification: D06 Code Developments and<br />

Simulation Techniques<br />

Poster Panel 72<br />

ID: 4312 - WEPC117<br />

A Matrix Presentation for a Beam Propagator<br />

including <strong>Particle</strong>s Spin, Michael Kosovtsov,<br />

Serge Andrianov, Andrey Ivanov (St. Petersburg<br />

State University, St. Petersburg) - <strong>Particle</strong>s beam<br />

dynamics in magnetic and electrical fields with spin<br />

is discussed. This approach provides a constructive<br />

method of matrix presentation derivation for a beam<br />

propagator in magnetic and electrical fields. The<br />

beam propagator is evaluated in according to the


well-known Lie algebraic tools. But in contrast to<br />

traditional approaches matrix presentation for Lie<br />

propagators bases on two-indexes matrices. This<br />

approach permit to apply all of matrix algebra<br />

opportunities and advantages in contrast with the<br />

tenzor presentation based on multi-indexes<br />

description. The necessary computation can be<br />

realized in symbolic (using computer algebra codes<br />

as Mathematica, Maple, Maxima and so on). The<br />

corresponding symbolic objects itself can be stored<br />

in special databases and used then in numerical<br />

computing. Parallel and distributed conception is<br />

well acceptable with the suggested matrix<br />

formalism. Some symbolic and numerical results are<br />

discussed for problems of long term evolution of<br />

particles with spin.<br />

Sub Classification: D06 Code Developments and<br />

Simulation Techniques<br />

Poster Panel 73<br />

ID: 3775 - WEPC080<br />

An Effective Model of the LHC to Understand<br />

the Measured Beta-beating, Maria Carmen Alabau<br />

Pons, Frank Schmidt, Rogelio Tomas (CERN,<br />

Geneva), Ewen Hamish Maclean (CERN, Geneva;<br />

JAI, Oxford) - An effective model of the LHC<br />

optics has been developed based on measurements<br />

of magnetic field, alignment errors and closed orbit.<br />

This model utilizes the Polymorphic Tracking Code<br />

with MAD-X as front-end to allow the inclusion of<br />

harmonics to an arbitrary order in thick lattice<br />

�<br />

22<br />

elements. Beta-beating calculations have been<br />

performed with this model at injection optics and at<br />

3.5 TeV squeezed to 3.5 m beta-function at the<br />

interaction point. The model predictions are in<br />

remarkable agreement with the measurements<br />

performed in the 2010 LHC commissioning run.<br />

Sub Classification: D06 Code Developments and<br />

Simulation Techniques<br />

Poster Panel 74<br />

ID: 1790 - WEPC109<br />

CSR Impedance for an Ultrarelativistic Beam<br />

moving in a Curved Trajectory, Demin Zhou,<br />

Kazuhito Ohmi (KEK, Ibaraki) - A dedicated<br />

computer code, CSRZ, has been developed to<br />

calculate the coherent synchrotron radiation (CSR)<br />

impedance for an ultrarelativistic beam moving in a<br />

curved trajectory. Following the pioneering work by<br />

T. Agoh and K. Yokoya, the code solves the<br />

parabolic equation in the frequency domain in a<br />

curvilinear coordinate system. The beam is assumed<br />

to move along a vacuum chamber which has a<br />

uniform rectangular cross section but with variable<br />

bending radius. In this paper, we illustrate the<br />

algorithms for numerical calculations and<br />

demonstrate some examples in which the<br />

interference between CSR generated in consecutive<br />

dipole magnets were considered.<br />

Sub Classification: D06 Code Developments and<br />

Simulation Techniques


�<br />

Classification 6: Beam Instrumentation and Feedback<br />

Poster Panel 75<br />

ID: 3808 - TUPC148<br />

Measuring Emittance with the MICE<br />

Scintillating Fibre Trackers, David Adey<br />

(University of Warwick, Coventry) - The Muon<br />

Ionization Cooling Experiment (MICE) aims to<br />

measure a 10% reduction in a muon beam emittance<br />

to within 0.1%. To achieve this two scintillating<br />

fibre trackers will be placed within a 4T solenoidal<br />

field. The trackers utilize fibres with a diameter of<br />

350 microns to provide a position resolution of less<br />

than 0.5 mm. Details of the tracker hardware,<br />

electronics and its calibration and reconstruction<br />

methods will be presented, along with the measured<br />

performance under cosmic ray tests and the<br />

simulated performance in MICE.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 76<br />

ID: 3621 - TUPC127<br />

Optical Transition Radiation System for ATF2,<br />

Javier Alabau-Gonzalvo, Cesar Blanch Gutierrez,<br />

Angeles Faus-Golfe, Juan Jose Garcia-Garrigos<br />

(IFIC, Valencia), Juan Cruz, Douglas McCormick,<br />

Glen White, Mark Woodley (SLAC, Menlo Park,<br />

California) - In this paper we present the first<br />

measurements performed during the fall 2010 and<br />

early 2011 runs. Software development, simulations<br />

and hardware improvements to the Multi-Optical<br />

Transition Radiation System installed in the beam<br />

diagnostic section of the Extraction (EXT) line of<br />

ATF2 are described. 2D emittance measurements<br />

have been performed and the system is being<br />

routinely used for coupling correction. Realistic<br />

beam simulations have been made and compared<br />

with the measurements. A 4D emittance procedure,<br />

yet to be implemented, is also discussed. A<br />

demagnifier lens system to improve the beam<br />

finding procedure has been designed and will be<br />

implemented in a future run. Finally, we discuss<br />

further verification work planned for the next run<br />

period of ATF.<br />

Funding Agency: FPA2010-21456-C02-01 Work<br />

supported in part by Department of Energy Contract<br />

DE-AC02-76SF00515<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

23<br />

Poster Panel 77<br />

ID: 3409 - TUPC076<br />

Realization of a High Bandwidth Bunch Arrival<br />

time Monitor with Cone-shaped Pickup<br />

Electrodes for FLASH and XFEL,<br />

Aleksandar Angelovski, Matthias Hansli, Rolf<br />

Jakoby, Alexander Kuhl, Andreas Penirschke,<br />

Sascha Schnepp (TU Darmstadt, Darmstadt), Holger<br />

Schlarb (DESY, Hamburg), Thomas Weiland<br />

(TEMF, TU Darmstadt, Darmstadt) - In the Free<br />

Electron Laser in Hamburg (FLASH) an electrooptical<br />

system is used as a Bunch Arrival time<br />

Monitor (BAM). The time-of-arrival resolution is<br />

proportional to the steepness of the beam pick-up<br />

signal at the first zero-crossing*. Future experiments<br />

will be conducted using significantly lower bunch<br />

charges resulting in a reduced signal steepness. This<br />

requires BAM pickup electrodes with increased<br />

bandwidth as introduced in **. This paper presents<br />

the implementation and measurement results of a<br />

high bandwidth cone-shaped pickup capable of<br />

operating in the frequency range up to 40 GHz. The<br />

slope steepness at the zero crossing is investigated<br />

for a simplified equivalent circuit model. RFmeasurements<br />

have been performed using a nonhermetic<br />

prototype of the BAM pickups for<br />

assessing the influence of manufacturing tolerances<br />

on the sensor performance. The measurements are<br />

compared to simulation results obtained by CST<br />

PARTICLE STUDIO®.<br />

* F. Loehl et al., Proc. of DIPAC2007, WEPB15, p.<br />

262 (2007).<br />

** A. Angelovski et al., "Pickup design for a high<br />

resolution Bunch Arrival time Monitor for FLASH<br />

and XFEL", DIPAC2011.<br />

Funding Agency : Funded by the Federal Ministry of<br />

Education and Research (BMBF): 05K10RDA<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 78<br />

ID: 3208 - TUPC124<br />

Laser Wire Emittance Measurement Line at<br />

CLIC, Hector Garcia, Yuri Alexandrovich<br />

Kubyshin (UPC, Barcelona), Daniel Schulte, Frank<br />

Stulle (CERN, Geneva), Grahame A. Blair (JAI,<br />

Oxford) - A precise measurement of the transverse<br />

beam size and beam emittances upstream of the final<br />

focus is essential for ensuring the full luminosity at<br />

future linear colliders. A scheme for the emittance


measurements at the RTML line of the CLIC using<br />

laser-wire beam profile monitors is described. A<br />

lattice of the measurement line is discussed and<br />

results of simulations of statistical and machinerelated<br />

errors and of their impact on the accuracy of<br />

the emittance reconstruction are given. Modes of<br />

operation of the laser wire system and its main<br />

characteristics are discussed.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 79<br />

ID: 3785 - TUPC077<br />

Investigations on High Sensitive Sensor Cavity<br />

for Longitudinal and Transversal Schottky for<br />

the CR at FAIR, Matthias Hansli, Aleksandar<br />

Angelovski, Rolf Jakoby, Andreas Penirschke (TU<br />

Darmstadt, Darmstadt), Peter Hülsmann (GSI,<br />

Darmstadt), Wolfgang Ackermann, Thomas<br />

Weiland (TEMF, TU Darmstadt, Darmstadt) - For<br />

the Collector Ring (CR) at the FAIR (Facility for<br />

Antiproton and Ion Research) accelerator complex a<br />

sensitive Schottky sensor is required. The CR covers<br />

different modes of operation, like pre-cooling of<br />

antiprotons at 3 GeV, pre-cooling of rare isotope<br />

beams at 740 MeV/u and an isochronous mode for<br />

mass measurements. For longitudinal Schottky<br />

measurements the concept of a resonant cavity had<br />

been introduced*. Due to limited space inside the<br />

ring integration of transversal Schottky is restricted<br />

to one plane only. In this paper the demands and<br />

required changes to implement also transversal<br />

Schottky measurements are discussed. An analysis<br />

of the expected signal characteristics featuring<br />

equivalent circuit are shown, as well as numerical<br />

full wave simulations of the cavity. The applied<br />

numerical models are based on the finite integration<br />

technique as well as on the finite element method<br />

and include explicitly the coupling to the pickupantennas.<br />

The signal analysis utilizes both a modal<br />

approach and a beam-induced excitaion using a<br />

wakefield approach.<br />

* M. Hansli, A. Penirschke, R. Jakoby, W.<br />

Kaufmann, W. Ackermann, T. Weiland,<br />

"Conceptual Design of a High Sensitive Versatile<br />

Schottky Sensor for the Collector Ring at FAIR",<br />

DIPAC2011.<br />

Funding Agency : Funded by the Federal Ministry of<br />

Education and Research (BMBF): 06DA90351<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

�<br />

24<br />

Poster Panel 80<br />

ID: 3150 - TUPC086<br />

A Setup for Single Shot Electro Optical Bunch<br />

Length Measurements at the ANKA Storage<br />

Ring, Nicole Hiller, Erhard Huttel, Anke-Susanne<br />

Mueller (KIT, Karlsruhe), Felix Lukas Mueller,<br />

Peter Peier, Volker Schlott (PSI, Villigen) - Single<br />

shot electro optical bunch length measurements,<br />

in particular using spectral decoding, are foreseen<br />

for the ANKA storage ring. This will allow to<br />

resolve fast changes of bunch deformation and<br />

structure during the low alpha operation (2-15 ps<br />

rms bunch length). This technique uses a chirped<br />

laser pulse to probe the field induced birefringence<br />

in an electro optical crystal. The laser pulse is then<br />

analyzed in a single shot spectrometer. To obtain the<br />

birefringence modulation one can either use the near<br />

field of the electron bunch (placing the crystal close<br />

to the electron bunch in the UHV system of the<br />

storage ring), or the far field (coherent synchrotron<br />

radiation in the THz range at a THz-/IR-Beamline).<br />

The laser needs to supply: sufficient tunability of<br />

pulse length, a wide spectrum to allow for a sub-ps<br />

resolution. Additionally it must provide a modelocked<br />

operation synchronized to the bunch<br />

revolution clock. For this purpose, a mode locked<br />

Ytterbium fibre laser system which operates at 1030<br />

nm has been developed at the Paul-Scherrer Institute<br />

in Switzerland. We give an overview over the<br />

experimental set up in the ANKA storage ring and<br />

the status of the project.<br />

Funding Agency: Supported by the Initiative and<br />

Networking Fund of the Helmholtz Association<br />

under VH-NG-320. Sponsored by the German<br />

Federal Ministry of Education and Research under<br />

contract number 05K10VKC<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 81<br />

ID: 3609 - TUPC118<br />

Test Results on Beam Position Resolution for<br />

Low-Q IP-BPM at KEK-ATF2, Si-Won Jang, Aeyoung<br />

Heo, Ji-Gwang Hwang, Eun-San Kim,<br />

Hyoung-Suk Kim (Kyungpook National University,<br />

Daegu), HyangKyu Park (CHEP, Daegu) - We have<br />

performed the beam tests on the beam position<br />

resolution for the Low-Q IP-BPM (Interaction Point-<br />

Beam Position Monitor) at ATF2 which is an<br />

accelerator test facility for the <strong>International</strong> Linear<br />

Collider. The main goals of KEK-ATF2 are to<br />

achieve beam size of 37 nm and beam resolution of<br />

nano-meter for beam stabilization. Resolution tests


for the Low-Q IP-BPM were performed with KEK<br />

BPM doublet in Jan. 2011. We got the results of<br />

beam position resolution 70 nm during the<br />

experimental periods and will present the detailed<br />

experimental procedures and results.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 82<br />

ID: 4043 - TUPC078<br />

The Impact of the Duty Cycle on Gamma-<br />

<strong>Particle</strong> Coincidence Measurements,<br />

Philipp Rudolf John, Jörg Leske, Norbert Pietralla<br />

(TU Darmstadt, Darmstadt) - Radioactive beam<br />

facilities (like REX-ISOLDE) deliver a great variety<br />

of different radioactive ion beams and thus open<br />

new possibilities for gamma-ray spectroscopy with<br />

radioactive isotopes. One of the challenges for the<br />

experimentalist is the high gamma-background. To<br />

obtain nearly background-free spectra a gammaparticle<br />

coincidence measurement in inverse<br />

kinematics is well suited. Also for stable beams this<br />

method offers a lot of advantages. A crucial point<br />

for experimentalists for such kind of experiments is<br />

the duty cycle and the beam structure of the<br />

accelerator. For a typical set-up, the effect of the<br />

duty cycle and beam structure, resulting from e.g.<br />

different ion-sources, on data acquisition and thus<br />

the experiment will be shown from the<br />

experimentalist's point of view. The results will be<br />

discussed for selected accelerators, i.e. UNILAC<br />

(GSI, Germany), REX-ISOLDE (CERN,<br />

Switzerland) and ATLAS (ANL, USA).<br />

Funding Agency Supported by BMBF under<br />

06DA9041I<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 83<br />

ID: 4262 - TUPC149<br />

Position Determination of Closely Spaced<br />

Bunches using Cavity BPMs,<br />

Nirav Yashvantray Joshi, Stewart Takashi Boogert,<br />

Francis Jamshyd Cullinan, Alexey Lyapin (JAI,<br />

Egham, Surrey) - Cavity Beam Position Monitor<br />

(BPM) systems with high-Q form a major part of<br />

precision position measurement diagnostics for<br />

linear accelerators with low emittance beam. Using<br />

cavity BPMs, the position resolution of less than 100<br />

nm has been demonstrated in single bunch mode<br />

operation. In the case of closely spaced bunches,<br />

where the decay time of the cavity is comparable to<br />

the time separation between bunches, the BPM<br />

�<br />

25<br />

signal from a bunch is polluted by the signal induced<br />

from the previous bunches in the same bunch-train.<br />

This paper discuss our ongoing work to develop the<br />

methods to extract the position of the closely spaced<br />

bunches using cavity BPMs. A signal subtraction<br />

code is being developed to remove the signal<br />

pollution from previous bunches and to determine<br />

the individual bunch position. Another code has<br />

been developed to simulate the BPM data for the<br />

cross check. Performance of the code is studied on<br />

the experimental and simulated data. Application of<br />

the analysis techniques to the linear colliders, such<br />

as <strong>International</strong> Linear Collider (ILC) and Compact<br />

LInear Collider (CLIC), are briefly discussed.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 84<br />

ID: 3528 - TUPC087<br />

Filling Pattern Measurements at the ANKA<br />

Storage Ring, Benjamin Kehrer, Nicole Hiller,<br />

Andre Hofmann, Erhard Huttel, Vitali Judin, Marit<br />

Klein, Sebastian Marsching, Anke-Susanne Mueller,<br />

Nigel John Smale (KIT, Karlsruhe) - For many<br />

accelerator physics studies, e.g. the investigation of<br />

coherent synchrotron radiation (CSR), a precise<br />

knowledge of the quantitative filling pattern (i.e. the<br />

number of electrons per bunch) is essential. This can<br />

be achieved by either using a linear detector (analog<br />

recording) or by employing the method of timecorrelated<br />

single photon counting (TCSPC). At the<br />

ANKA storage ring both methods are in use. The<br />

analogue detection is based on the signal from a<br />

stripline or annular electrode, the TCSPC uses a<br />

Single Photon Avalanche Diode (SPAD). In this<br />

paper, we describe the experimental set-ups and<br />

present results of a comparison of the two<br />

techniques for single as well as for multi bunch<br />

filling patterns. Special emphasis is put on the<br />

response of the individual methods to a large<br />

dynamic range of beam currents and bunch lengths.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 85<br />

ID: 3929 - TUPC119<br />

A Comprehensive Study of Nanometer<br />

Resolution of the IPBPM, YoungIm Kim,<br />

Hwanbae Park (Kyungpook National University,<br />

Daegu), Yosuke Honda, Ryuhei Sugahara, Toshiaki<br />

Tauchi, Nobuhiro Terunuma, Junji Urakawa (KEK,<br />

Ibaraki), Stewart Takashi Boogert (Royal Holloway,<br />

University of London, Surrey), Josef Frisch,


Douglas McCormick, Janice Nelson, Tonee Smith,<br />

Glen White, Mark Woodley (SLAC, Menlo Park,<br />

California) - High-resolution beam position<br />

monitors (IPBPMs) have been developed in order to<br />

measure the electron beam position at the focus<br />

point of ATF2 to a few nanometers in the vertical<br />

plane. To date, the IPBPM system has operated in<br />

test mode with a highest demonstrated resolution of<br />

8.7 nm in the ATF extraction line during 2008. After<br />

expected noise source calculations there still remains<br />

7.9 nm of noise of unexplained origin. We<br />

summarize the experimental work on the IPBPM<br />

system since this measurement and outline the<br />

possible origins of these sources. We then present a<br />

study plan to be performed at the ATF2 facility<br />

designed to identify and to improve the resolution<br />

performance and comment on the expected ultimate<br />

resolution of this system.<br />

Funding Agency: Work supported in part by<br />

Department of Energy Contract DE-AC02-<br />

76SF00515.<br />

Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 86<br />

ID: 3632 - TUPC109<br />

Electron Bunch Slice Emittance Measurement<br />

with a Solenoid considering the Space Charge<br />

Effects, Chen Li, Ying-Chao Du, Chuanxiang Tang<br />

(TUB, Beijing) - Slice transverse emittance of the<br />

electron beam is critical to a high-gain shortwavelength<br />

FEL, thus its characterization is very<br />

important. For space charge dominated electron<br />

beam, conventional emittance measurement<br />

techniques, such as solenoid scan and quadruple<br />

scan, without considering space charge forces lead<br />

to large errors of emittance evaluations. This paper<br />

introduces the method of slice emittance<br />

measurement for space charge dominated electron<br />

beam, and slice emittance characterizaiton of<br />

electron beam by using a solenoid and a RF<br />

deflecting cavity has been performed at Tsinghua<br />

University. Simulations show that the new method<br />

brings the emittance evaluations much closer to<br />

actual values, and preliminary experiment results<br />

revealed considerable variations of slice emittance<br />

along the bunch, and core slice emittance was<br />

measured to be 0.52 mm.mrad for laser rms radius<br />

0.4 mm.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

�<br />

26<br />

Poster Panel 87<br />

ID: 2969 - TUPC108<br />

Beam Diagnostics Based on Higher Order Mode<br />

Measurement for ERL, Xing Luo, Xiangyang Lu<br />

(PKU/IHIP, Beijing) - A conceptual design of beam<br />

diagnostics based on higher order mode (HOM)<br />

measurement has been accomplished. The signals<br />

from the HOM ports on superconducting cavities<br />

can be used as beam position monitors and to do<br />

survey structure alignment. The induced HOM<br />

amplitude of dipole mode is proportional to the<br />

beam offset and can be used to measure the beam<br />

position inside the cavity. The phase of the<br />

monopole modes can be used to measure the phase<br />

of both accelerating beam and recirculating beam,<br />

which is critical for ERL. For multi-bunch<br />

operation, the signals from the HOMs induced by<br />

previous bunches can be subtracted to measure beam<br />

on each bunch.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 88<br />

ID: 3620 - TUPC141<br />

LHC Beam Loss Pattern Recognition,<br />

Aurelien Marsili, Eva Barbara Holzer (CERN,<br />

Geneva) - One of the systems protecting CERN's<br />

Large Hadron Collider (LHC) is the Beam Loss<br />

Monitoring system (BLM). More than 3600<br />

monitors are installed around the ring. The beam<br />

losses are permanently integrated over 12 different<br />

time intervals (from 40 microseconds to 84<br />

seconds). When any loss exceeds the thresholds<br />

defined for the integration window, the beam is<br />

removed from the machine. Understanding the<br />

origin of a beam loss is crucial for machine<br />

operation, as it can help to avoid a repeat of the<br />

same scenario. The signals read from given monitors<br />

can be considered as entries of a vector. This article<br />

presents how a loss map of unknown cause can be<br />

decomposed using vector based analysis derived<br />

from well-known loss scenarios. The algorithms<br />

achieving this decomposition are described, as well<br />

as the accuracy of the results.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 89<br />

ID: 3028 - TUPC063<br />

Energy Verification in Ion Beam Therapy,<br />

Fabian Moser (ATI, Wien), Michael Benedikt<br />

(CERN, Geneva; EBG MedAustron, Wr. Neustadt),<br />

Ulrich Dorda (EBG MedAustron, Wr. Neustadt -


The adaptation of synchrotrons for medical<br />

applications necessitates a comprehensive on-line<br />

verification of all beam parameters, autonomous of<br />

common beam monitors. In particular for energy<br />

verification, the required precision of down to 0.1<br />

MeV, in absolute terms, poses a special challenge<br />

regarding the betatron-core driven 3rd order<br />

extraction mechanism which is intended to be used<br />

at MedAustron. Two different energy verification<br />

options have been studied and their limiting factors<br />

were investigated: 1) A time-of-flight measurement<br />

inside the synchrotron, limited by the orbit<br />

circumference information and measurement<br />

duration as well as extraction uncertainties. 2) A<br />

calorimeter-style system in the extraction line,<br />

limited by radiation hardness and statistical<br />

fluctuations. The paper discusses in detail the<br />

benefits and specific aspects of each method.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 90<br />

ID: 4129 - TUPC158<br />

Micron-scale Laser-wire at the <strong>Accelerator</strong> Test<br />

Facility 2 at KEK Commissioning and Results,<br />

Laurence James Nevay, Grahame A. Blair, Laura<br />

Corner, Roman Walczak (JAI, Oxford), Stewart<br />

Takashi Boogert, Lawrence Charles Deacon (JAI,<br />

Egham, Surrey), Alexander S. Aryshev, Nobuhiro<br />

Terunuma, Junji Urakawa (KEK, Ibaraki) - We<br />

present the first results from the commissioning of<br />

the upgraded laser-wire experiment at the<br />

<strong>Accelerator</strong> Test Facility 2 (ATF2) at KEK. A new<br />

laser transport line and beam diagnostics were used<br />

to collide 150 mJ, 167 ps long laser pulses with 1.28<br />

GeV, 30 ps long electron bunches to measure the<br />

vertical transverse size. Additionally, a new detector<br />

was installed with a reduced area for lower<br />

background. Initial scans showing a convoluted<br />

beam size of 19.2 ± 0.2 microns were used to tune<br />

the electron beam optics and reduce this down to 8.1<br />

± 0.1 microns. Laser pulse energy and charge<br />

dependency were investigated showing a linear<br />

relationship in both with a minimum laser energy of<br />

20 mJ required for observable signal with this laser<br />

and setup.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 91<br />

ID: 3270 - TUPC117<br />

Embedded EPICS IOC Data Acquisition System<br />

for Beam Instability Research, Ning Zhang<br />

�<br />

27<br />

(SSRF, Shanghai) - In SSRF, an embedded data<br />

acquisition (DAQ) system based on high-<br />

performance digital oscilloscope for bunch by bunch<br />

BPM data acquisition is developed, which can be<br />

used for acquiring bunch by bunch beam parameters<br />

such as beam current and beam position in storage<br />

ring. Signals from BPM would be digitized and raw<br />

data would be stored directly in the memory of<br />

oscilloscope and processed by embedded EPICS<br />

IOC C programming Algorithm. This system is<br />

processed in time domain and wideband mode,<br />

compared with frequency domain and narrowband<br />

method for some traditional electronics solutions. It<br />

is used for observing the change of beam running<br />

condition, especially hoped to record the whole<br />

process that beam is just injected into storage ring.<br />

And by data analysis, we can study for beam<br />

instability. For more research, we have also<br />

analyzed the frequency domain of excited electron<br />

beam position signal, and get the Tune and quality<br />

factor Q which is related with damping and<br />

frequency dispersing. Tune and Q can reflect beam<br />

instability and by doing this, we will research how<br />

beam instability is generated. Data acquisition<br />

system and data analysis will be described in detail<br />

in this paper.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 92<br />

ID: 3089 - TUPC156<br />

Beam Alignment Based on Higher Order Modes<br />

in Third Harmonic Superconducting Cavities at<br />

FLASH, Pei Zhang (DESY, Hamburg; UMAN,<br />

Manchester), Nicoleta Baboi (DESY, Hamburg),<br />

Roger Michael Jones, Ian Reginald Roy Shinton<br />

(UMAN, Manchester) - Off-axis beams passing<br />

through a cavity excite dipole modes. These modes<br />

have linear dependencies on the beam offset from<br />

the cavity axis; therefore they can be used to<br />

monitor the beam position within the cavity. The<br />

fifth order of dipole band of the 3.9 GHz third<br />

harmonic superconducting cavities at FLASH has<br />

modes trapped within each cavity and cannot<br />

propagate through the adjacent beam pipes; this<br />

could enable the beam alignment in individual<br />

cavities. This paper investigates the possibility to<br />

use the fifth dipole band for beam alignment in the<br />

3rd harmonic module, consisting of four cavities.<br />

Simulations and measurements both with and<br />

without beam excitations are presented. Various<br />

analysis methods are used and compared.


Funding Agency: Work supported by European<br />

Commission under the FP7 Research Infrastructures<br />

grant agreement No. 227579.<br />

Sub Classification: T03 Beam Diagnostics and<br />

Instrumentation<br />

Poster Panel 93<br />

ID: 3376 - MOPO005<br />

A Transverse Feedback System using Multiple<br />

Pickups for Noise Minimization,<br />

Mouhammad Alhumaidi, Abdelhak M. Zoubir (TU<br />

Darmstadt, Darmstadt) - A new concept for using<br />

multiple pickups for estimating beam angle at the<br />

kicker is addressed. The estimated signal should be<br />

the driving feedback signal. The signals from the<br />

different pickups are delayed, such that they<br />

correspond to the same bunch. Consequently a<br />

weighted sum of the delayed signals is suggested as<br />

an estimator of the beam angle at the kicker. The<br />

weighting coefficients are calculated such that the<br />

estimator is unbiased, i.e. the output corresponds to<br />

the actual beam angle at the kicker for non-noisy<br />

pickup signals. Furthermore, the estimator must give<br />

the minimal noise power at the output among all<br />

linear unbiased estimators. Finally results for the<br />

heavy ions synchrotron SIS 18 at the GSI are shown.<br />

Sub Classification: T05 Beam Feedback Systems<br />

Poster Panel 94<br />

ID: 3204 - WEPC166<br />

Monte Carlo Simulation of the Total Dose<br />

Distribution Around the 12 MeV UPC Racetrack<br />

Microtron and Radiation Shielding<br />

Calculations, Cristina de la Fuente, Maria Amor<br />

Duch, Yuri Alexandrovich Kubyshin (UPC,<br />

Barcelona), Vasiliy Ivanovich Shvedunov (MSU,<br />

Moscow) - The Technical University of Catalonia is<br />

building a miniature 12 MeV electron race-track<br />

microtron for medical applications. In the paper we<br />

study the leakage radiation caused by beam losses<br />

�<br />

28<br />

inside the accelerator head, as well as the<br />

bremstrahlung radiation produced by the primary<br />

beam in the commissioning setting. Results of<br />

Monte Carlo simulations using the PENELOPE code<br />

are presented and two shielding schemes, global and<br />

local, are studied. The obtained shielding parameters<br />

are compared with estimates based on international<br />

recommendations of the radiation safety standards.<br />

Sub Classification: T18 Radiation Monitoring and<br />

Safety<br />

Poster Panel 95<br />

ID: 3612 - WEPC174<br />

Beam-induced Quench Test of LHC Main<br />

Quadrupole, Agnieszka Priebe (CERN, Geneva;<br />

EPFL, Lausanne), Knud Dahlerup-Petersen, Bernd<br />

Dehning, Ewald Effinger, Jonathan Emery, Eva<br />

Barbara Holzer, Christoph Kurfuerst, Eduardo<br />

Nebot Del Busto, Annika Nordt, Mariusz Sapinski,<br />

Jens Steckert, Arjan Verweij, Christos Zamantzas<br />

(CERN, Geneva) - Unexpected beam loss might lead<br />

to transition of a superconducting accelerator<br />

magnet to a normal conducting state. The LHC<br />

beam loss monitoring (BLM) system is designed to<br />

abort the beam before the energy deposited in the<br />

magnet coils reaches a quench-provoking level. In<br />

order to verify the threshold settings generated by<br />

simulation, a series of beam-induced quench tests at<br />

various beam energies have been performed. The<br />

beam losses are generated by means of an orbit<br />

bump peaked in one of the main quadrupole<br />

magnets. The analysis not only includes BLM data<br />

but also data from the electrical quench protection<br />

and cryogenic systems. The measurements are<br />

compared to Geant4 simulations of energy<br />

deposition inside the coils and corresponding BLM<br />

signal outside the cryostat. The results are also<br />

extrapolated to higher beam energies.<br />

Sub Classification: T23 Machine Protection


Poster Panel 96<br />

ID: 4061 - MOPC046<br />

CaCo: A Cavity Combiner for IOTs Amplifiers,<br />

Beatriz Bravo, Filip Mares, Francis Perez, Paco<br />

Sanchez (CELLS-ALBA Synchrotron, Cerdanyola<br />

del Vallès), Michel Langlois (ESRF, Grenoble) -<br />

The ALBA storage ring uses six room temperature<br />

cavities; each one fed by two 80 kW IOTs amplifiers<br />

at 499.654 MHz. The power of the pair of<br />

transmitters is combined by a cavity combiner,<br />

CaCo. One of the design requirements of CaCo was<br />

that it continued working safely and with a good<br />

efficiency in the case of an IOT failure<br />

(asymmetrical mode). During the first asymmetric<br />

full power tests, in May 2010, with an active IOT<br />

and the other passive, the result was dramatic, the<br />

passive IOT broke in two parts after few hours of<br />

operation. This paper presents the experimental<br />

results and the electromagnetic field simulations of<br />

the asymmetrical operation mode of CaCo, i.e. one<br />

active IOT and the other passive, and analyze why<br />

the ceramic of the output tube of the passive IOT<br />

broke during the first performance of this mode.<br />

Also, it reports a possible solution to solve this<br />

problem.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 97<br />

ID: 3351 - MOPC002<br />

Cooling and Vibration Studies for the CLIC Xband<br />

Accelerating Structures, Tessa Charles, Kris<br />

Ryan (Monash University, Melbourne), Mark James<br />

Boland (ASCo, Clayton, Victoria), Germana<br />

Riddone (CERN, Geneva), Alexander Samoshkin<br />

(JINR, Dubna, Moscow Region) - Turbulent cooling<br />

water in the Compact Linear Collider (CLIC)<br />

accelerating structures will inevitably induce some<br />

vibrations. The maximum acceptable amplitude of<br />

vibrations is small, as vibrations in the accelerating<br />

structure could lead to beam jitter and alignment<br />

difficulties. A FEM model is needed to identify the<br />

conditions under which vortex shedding from the<br />

cooling system induces significant vibrations. Due<br />

to the orders of magnitude difference between the<br />

fluid motion and the structure motion, vibrations of<br />

the structure will make a negligible contribute to the<br />

turbulence of the cooling fluid. Therefore the<br />

resonant conditions of the cooling channels,<br />

presented in this paper, determine directly the<br />

natural frequencies of the accelerating structures,<br />

�<br />

Main Classification 7: <strong>Accelerator</strong> Technology<br />

29<br />

thereby identifying frequencies to be avoided under<br />

normal operating conditions. These results will be<br />

applied to the final structural design of the<br />

accelerating structures. This paper also identifies the<br />

positioning of sensors for the CLIC Two-Beam Test<br />

Module.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 98<br />

ID: 2026 - MOPC030<br />

The C-band Traveling-wave Accelerating<br />

Structure for Compact XFEL at SINAP,<br />

Wencheng Fang, Qiang Gu, Zhentang Zhao<br />

(SINAP, Shanghai), Dechun Tong (TUB, Beijing) -<br />

The R&D of C-band accelerating structure has been<br />

launched two years ago at Shanghai Institute of<br />

Applied Physics, it will be used for the future<br />

compact hard X-ray FEL. The 1st C-band travelingwave<br />

accelerating structure is ready for the high<br />

power test now. This structure is the preliminary<br />

model for the research of the technology of<br />

microwave test and tuning, arts and crafts and high<br />

power test. This paper presents the process of<br />

fabrication, cold test and tuning results.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 99<br />

ID: 4447 - MOPC065<br />

Ion Motion in the Vicinity of Microprotrusions in<br />

Accelerating Structures, Dmytro Kashyn, Tom<br />

Antonsen, Irving Haber, Gregory Nusinovich<br />

(UMD, College Park, Maryland) - It is known that<br />

newly fabricated accelerating structures have almost<br />

ideally smooth surface. However, ‘post mortem’<br />

examination of these structures reveals that their<br />

surface can be significantly modified after highgradient<br />

operation. This surface modification can be<br />

caused by the appearance of microscopic<br />

protrusions*. One of the factors leading to heating,<br />

melting and evaporation of these protrusions (factors<br />

resulting in the RF breakdown) is ion<br />

bombardment**. In our study we analyze ion motion<br />

in the vicinity of microprotrusions both analytically<br />

and numerically. First, we study the ion motion in<br />

the RF electric field magnified by the protrusion in<br />

the absence of electron field emitted current and<br />

show that most of the ions do not reach the structure<br />

surface. Then we add into consideration the<br />

interaction of ions with Fowler-Nordheim current<br />

emitted from the tip of protrusion (dark current).


First, we develop a model describing this interaction<br />

and then we supplement it with numerical results<br />

using PIC code WARP***. We show that the ions<br />

move towards the area occupied by the dark current,<br />

but this does not increase the bombardment of<br />

micro-protrusions.<br />

* R.B. Palmer,et al, Phys. Rev ST Accel. Beams 12,<br />

031002 (2009).<br />

** P. Wilson, AIP Conf. Proc., 877, Melville, New<br />

York, 2006, p. 27.<br />

*** J.-L. Vay, et al, Physics of Plasmas, 11, 2928<br />

(2004).<br />

Funding Agency: This work is supported by Office<br />

of High Energy Physics of the U.S. Department of<br />

Energy.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 100<br />

ID: 4471 - MOPC066<br />

Role of Nottingham and Thomson Effects in<br />

Heating of Micro-protrusion in High-gradient<br />

Accelerating Structures, Aydin Cem Keser, Tom<br />

Antonsen, Dmytro Kashyn, Gregory Nusinovich<br />

(UMD, College Park, Maryland) - It is widely<br />

accepted that one of the reasons for appearance of<br />

the RF breakdown which limits operation of highgradient<br />

accelerating structures is the electron dark<br />

current*. This field emitted current, usually<br />

considered as a precursor of the breakdown, can be<br />

emitted from apexes of microprotrusions on a<br />

structure surface. Therefore field and thermal<br />

processes in such protrusions deserve careful<br />

studies**. The goal of our first study*** was to<br />

analyze 2D process of RF field penetration inside<br />

protrusion of a metal with finite conductivity and to<br />

study corresponding Joule heating. In the present<br />

study, we include into consideration, first, the<br />

Nottingham effect which may significantly change<br />

the protrusion heating. Then, since protrusion<br />

heating in high-power, short-pulse operation can be<br />

strongly non-uniform, we include into consideration<br />

also Thomson effect which predicts additional<br />

heating/cooling in non-uniformly heated conductors.<br />

* Wang and Loew, SLAC-pub-7684,1997<br />

** K.L.Jensen,Y.Y. Lau, D.W. Feldman, P.G.<br />

O'Shea, Phys. Rev. ST Accel.Beams 11,<br />

081001(2008)<br />

*** Kashyn et al, AAC-2010.<br />

Sub Classification: T06 Room Temperature RF<br />

�<br />

30<br />

Poster Panel 101<br />

ID: 3159 - MOPC022<br />

Development of a Compact C-band Photocathode<br />

RF Gun, Xiaohan Liu, Chuanxiang Tang (TUB,<br />

Beijing) - A C-band photocathode RF gun for a<br />

compact electron diffraction facility is developed in<br />

Tsinghua University, which is designed to work at<br />

the frequency of 5.712GHz. This paper presents the<br />

physics and structure design of this C-band RF gun,<br />

and the comparison on beam dynamics of S-band<br />

and C-band photoinjector has been done. Some new<br />

structure design will be adopted in this gun,<br />

including the optimized cavity length and elliptical<br />

iris, which is helpful to achieve lower emittance and<br />

larger mode separation. This paper likewise presents<br />

experiment parameters and the preliminary cold test<br />

results of this C-band RF gun.<br />

Funding Agency This work is supported by<br />

National Natural Science Foundation of China and<br />

National Basic Research Program of China (973<br />

Program).<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 102<br />

ID: 1866 - MOPC026<br />

A-core Loaded Untuned RF Compression Cavity<br />

for HIRFL-CSR, Lirong Mei, Zhe Xu, Youjin<br />

Yuan, Hongwei Zhao (IMP, Lanzhou) - To meet the<br />

requirement of conducting high energy density and<br />

plasma physics research at HIRFL-CSR. The higher<br />

accelerating gap voltage was required. A magnetic<br />

alloy (MA)-core loaded radio frequency (RF) cavity<br />

which can provide higher accelerating gap voltage<br />

has been studied in Institute of Modern Physics,<br />

Chinese Academy of Sciences (IMP, CAS),<br />

Lanzhou. To select proper MA material to load the<br />

RF compression cavity, measurement for MA cores<br />

has been conducted. The MA core with higher<br />

permeability and shunt impedance, and lower<br />

quality factor (Q value) should be selected. The<br />

theoretical calculation and simulation for the MAcore<br />

loaded RF cavity can be consistent with each<br />

other well. Finally 230kW power was needed to<br />

meet 50-kV accelerating gap voltage by calculation.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 103<br />

ID: 3198 - MOPC040<br />

The Measurement of Transversal Shunt<br />

Impedance of RF Deflector, Aleksandr Smirnov,<br />

Michael Vladimirovich Lalayan, Nicolay Sobenin<br />

(MEPhI, Moscow), Aleksandr Alekseevich<br />

Zavadtsev (Nano, Moscow) - This paper presents the


esults of transverse shunt impedance measurement<br />

performed using field perturbation technique and<br />

comparison with numerical MWS simulations. The<br />

structure under test is the S-band 3-cell deflecting<br />

cavity. The mentioned cavity operates with a dipole<br />

TM11-like mode with a phase shift of 120 deg per<br />

cell. The analyses were carried out with use of two<br />

types of perturbing beads: dielectric beads and<br />

metallic rings. The latter type perturbs the on-axis<br />

magnetic field much stronger than the electric field,<br />

which allows us calculating transversal shunt<br />

impedance using on-axis EM fields values.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 104<br />

ID: 3355 - MOPC035<br />

Design and Machine Features of 2.2-m C-band<br />

Accelerating Structure, Changho Yi, Moo-Hyun<br />

Cho, Sang-Hoon Kim, Huijea Lee (POSTECH,<br />

Pohang, Kyungbuk), Won Namkung (PAL, Pohang,<br />

Kyungbuk) - In order to make a compact linac<br />

system, it is necessary in reducing the number of RF<br />

power modules. It would be effective use of the RF<br />

power. As the accelerating column is longer, the RF<br />

power would be used more effectively. However,<br />

longer column has a lower accelerating gradient.<br />

Since the existing accelerating column is operated at<br />

a lower accelerating gradient than its maximum<br />

capability for stable operations, there is a certain<br />

margin in reducing the accelerating gradient. We<br />

propose a 2.2-m long accelerating column. It is 22%<br />

longer than the 1.8-m C-band accelerating column at<br />

XFEL/SPring-8. In this paper, we present details of<br />

the column design and machine features including<br />

RF characteristics, vacuum performance and thermal<br />

stability analyzed by an analytic model.<br />

Funding Agency: Work partly supported by MEST<br />

and POSTECH Physics BK21 Program.<br />

Sub Classification: T06 Room Temperature RF<br />

Poster Panel 105<br />

ID: 1868 - MOPC028<br />

Beam Acceleration of DPIS RFQ at IMP,<br />

Zhouli Zhang (IMP, Lanzhou) - An RFQ has been<br />

designed and built at IMP, CAS. It has been put into<br />

operation by the end of 2010 for the direct plasma<br />

injection scheme (DPIS) of IMP. Here the DPIS<br />

experiment is introduced in detail, and experiments<br />

results are given.<br />

Sub Classification: T06 Room Temperature RF<br />

�<br />

31<br />

Poster Panel 106<br />

ID: 2566 - MOPC088<br />

Bead-pull Measurement using Phase-Shift<br />

Technique in Multi-cell Elliptical Cavity,<br />

Surajit Ghosh, Aditya Mandal, Sudeshna Seth,<br />

Sumit Som (DAE/VECC, Calcutta) - The project on<br />

the development of high-beta multi-cell elliptical<br />

shape superconducting rf linac cavity at around 704<br />

MHz has been funded at VECC, Kolkata, India. A<br />

full-scale copper prototype cavity has been designed<br />

and fabricated. There are 5 distinct modes exist in<br />

the cavity and the accelerating mode is pi-mode in<br />

which each cell operates at same frequency with<br />

phase difference of 180 degrees between two<br />

neighboring cells. A fully automated bead-pull<br />

measurement setup has been developed for<br />

analyzing these modes and field profile distribution<br />

at different modes in such type of linac cavity. A<br />

special measurement method inside the cavity using<br />

phase-shift technique is proposed in this paper,<br />

which describes the development of mechanical<br />

setup comprising pulleys and stepper motor–gear<br />

arrangement, PC-based control system for precise<br />

movement of bead using stepper motor,<br />

measurement using VNA, development of software<br />

for data acquisition & automation and measurement<br />

results for the 5-cell copper prototype cavity.<br />

Sub Classification: T07 Superconducting RF<br />

Poster Panel 107<br />

ID: 3366 - MOPC096<br />

Design of a 5-Cell High Current Superconducting<br />

Cavity, Yongming Li, Kexin Liu, Shengwen Quan,<br />

Feng Zhu (PKU/IHIP, Beijing), Ali Nassiri (ANL,<br />

Argonne) - ergy recovery linacs (ERL) is promising<br />

to achieve high average current with superior beam<br />

quality. The key component for accelerating such<br />

high current beams is the superconducting radio<br />

frequency (SRF) cavity. The design of a 1.3 GHz 5cell<br />

high current superconducting cavity has been<br />

carried out under the cooperation between Peking<br />

University (PKU) and Argonne National Laboratory<br />

(ANL). RF properties, damping of the HOMs,<br />

multipacting and mechanical features of this cavity<br />

have been discussed and the final design is presented.<br />

Funding Agency National High Technology<br />

Research and Development program 863<br />

(2009AA03Z206)<br />

Sub Classification T07 Superconducting RF


Poster Panel 108<br />

ID: 3228 - MOPC108<br />

Cornell SRF New Materials Program,<br />

Sam Posen, Matthias Liepe, Yi Xie (CLASSE,<br />

Ithaca, New York) - The performance of bulk<br />

niobium accelerator cavities has come very close to<br />

its fundamental limit set by the critical magnetic<br />

field. To continue progress, the SRF group at<br />

Cornell has recently pioneered an extensive program<br />

to investigate new implementations of<br />

superconducting cavities. We have developed<br />

facilities to fabricate Nb3Sn, a superconductor<br />

which will theoretically be able to reach more than<br />

twice the maximum accelerating field of Nb in a<br />

cavity under the same operating conditions. In<br />

addition, with the critical temperature of Nb3Sn<br />

being twice that of Nb, Nb3Sn would allow<br />

operating SRF cavities with a much higher<br />

cryogenic efficiency. We have also manufactured<br />

TE cavities that measure the RF properties of small,<br />

flat samples, ideal for material fabrication methods<br />

in development. The shape of one of these cavities<br />

puts significantly higher fields on the sample than on<br />

the niobium cavity, allowing direct study of fields<br />

higher than would be observable in any normal<br />

cavity tests, a unique capability. This paper presents<br />

an overview of the materials research program. First<br />

results from tests of Nb3Sn samples are presented.<br />

Funding Agency: NSF<br />

Sub Classification: T07 Superconducting RF<br />

Poster Panel 109<br />

ID: 3220 - MOPC085<br />

Establishing High Yield for High-gradient<br />

Cavities, Felix Schlander, Sebastian Aderhold,<br />

Eckhard Elsen, Detlef Reschke, Marc Wenskat<br />

(DESY, Hamburg) - A series of some 600<br />

superconducting 1.3 GHz cavities will start being<br />

delivered to DESY by industry in early 2012.<br />

Although a considerably smaller gradient satisfies<br />

the needs for the European XFEL the electropolished<br />

cavities (50% of the delivery) are deemed<br />

to be suitable for gradients in excess of 35 MV/m,<br />

the performance goal of the <strong>International</strong> Linear<br />

Collider (ILC). Specifically 24 cavities will be<br />

supplied without helium tank to enable further<br />

investigations. The results may serve to improve<br />

overall performance; limitations such as field<br />

emission and thermal breakdown of<br />

superconductivity ("quench") are still under<br />

investigation. For this matter the DESY ILC group<br />

has developed tools to monitor aspects of the cavity<br />

fabrication. An automated optical mapping system<br />

�<br />

32<br />

(OBACHT) is being commissioned and will be<br />

complemented by software for automated cavity<br />

surface feature recognition. For cold RF tests a<br />

Second Sound setup for locating the positions of the<br />

thermal breakdown is routinely used. These<br />

diagnostic tools will give guidance on postprocessing<br />

cavities for best performance. The<br />

current status of these projects will be described.<br />

Funding Agency: This work is supported by the<br />

Commission of the European Communities under<br />

the 7th Framework Programme “Construction of<br />

New Infrastructures – Preparatory Phase”, contract<br />

number 206711.<br />

Sub Classification: T07 Superconducting RF<br />

Poster Panel 110<br />

ID: 3580 - WEPO019<br />

Magnetic Model of the CERN Proton<br />

Synchrotron Main Magnetic Unit,<br />

Mariusz Juchno (EPFL, Lausanne) - The CERN<br />

Proton Synchrotron (PS) will remain one of the key<br />

elements of the Large Hadron Collider (LHC)<br />

injector system for next 20-25 years. An accurate<br />

magnetic model of its combined-function magnets<br />

will be essential in trimming the machine<br />

characteristics to the requirements for the LHC and<br />

its upgrades. A detailed 2D quasi-static analysis of<br />

the PS magnets and their correction circuits allowed<br />

to set-up a magnetic model taking into consideration<br />

the magnetic field evolution and contribution of<br />

separate magnet circuits at different field levels. An<br />

experimental validation of the model is being carried<br />

out through ad-hoc field measurements machine<br />

studies iterated with a MAD-X model of the PS<br />

machine to recreate the measured optical parameters<br />

of the beam.<br />

Sub Classification: T09 Room-Temperature<br />

Magnets<br />

Poster Panel 111<br />

ID: 3237 - WEPO011<br />

Design study of Electromagnet for 13MeV PET<br />

Cyclotron, Byeong-No Lee, Jong-Seo Chai, Hyun<br />

Wook Kim, Jin Hwan Oh, HoSeung Song (SKKU,<br />

Suwon) - Cyclotron magnet for RI production which<br />

used for PET scanning has been designed. Designed<br />

pancake-shape magnet is advanced type of<br />

KIRAMS-13*'s H-type Magnet. The AVF structure<br />

with 20 ratio of hill and valley used for getting<br />

strong axial focusing and produced the energy of<br />

proton beam up to 13MeV with thin stripper foil. To<br />

design and analyze the magnet CAD and TOSCA<br />

were used, respectively. Footnotes KIRAMS-13* is


the cyclotron had been manufactured by KIRAMS.<br />

KIRAMS is short for Korea Institutes of<br />

Radiological and Medical Science.<br />

Funding Agency National Research Foundation of<br />

Korea<br />

Sub Classification: T09 Room-Temperature<br />

Magnets<br />

Poster Panel 112<br />

ID: 2686 - THPO004<br />

An Active Power Filter Based on Wavelet<br />

Analysis, Xiaoling Guo (Private Address, Beijing;<br />

IHEP Beijng, Beijing) - As modern accelerator<br />

demands a magnet supply with a much higher<br />

stability, it is important to improve the quality of the<br />

magnet supply. An effective method to improve the<br />

output performance active power filter (APF)<br />

applied in current supply is proposed. To lowdown<br />

the harmonic constituents, the APF circuit generates<br />

a harmonic current, which added to the current from<br />

the main power supply, to countervail the ones in the<br />

supply’s current. At end of this paper, a simulation<br />

result is given to prove the effect of APF.<br />

Sub Classification: T11 Power Supplies<br />

Poster Panel 113<br />

ID: 1926 - THPO006<br />

A Digital Power Supply Control Model in Heavyion<br />

Therapy <strong>Accelerator</strong> Based on Dual Nios<br />

Cores, Rongkun Wang (Graduate University,<br />

Beijing; IMP, Lanzhou), Youxin Chen, Daqing<br />

Gao, Huaihai Yan, Zhongzu Zhou (IMP, Lanzhou) -<br />

DC and Pulse is the basic running models of magnet<br />

power supply in Heavy-Ion Therapy <strong>Accelerator</strong>.<br />

According to the character of digital power supply<br />

and the requirement of Pulse model. This paper<br />

introduce a Digital Power Supply Control Model<br />

(DPSCM) in Heavy-Ion Therapy <strong>Accelerator</strong> based<br />

on dual Nios cores, which can meet the requirement<br />

of two basic running models. The new method<br />

develops a system on-chip based on dual Nios cores<br />

by SOPC technology in the Altera EP2C35 FPGA.<br />

Communication, data processing is completed by<br />

one core and reference current setting is completed<br />

by another core. Compared with traditional DPSCM,<br />

the dual Nios cores run simultaneously and<br />

cooperate well, and the system efficiency is<br />

remarkably improved, further, cores in parallel can<br />

realize reference waveforms switch in pulse model<br />

effectively. This paper chooses a model machine in<br />

Heavy-Ion Therapy Facility in Lanzhou (HITFiL) as<br />

test bench. Experimental results indicate that the<br />

system can realize the function of pulse model, and<br />

�<br />

33<br />

the stability and current error meet the design<br />

requirements.<br />

Sub Classification: T11 Power Supplies<br />

Poster Panel 114<br />

ID: 3387 - TUPS007<br />

SIS100 Prototype Cryocatcher, Lars Bozyk,<br />

Dieter H.H. Hoffmann (TU Darmstadt, Darmstadt),<br />

Holger Kollmus, Peter J. Spiller (GSI, Darmstadt) -<br />

The main accelerator, SIS100, of the FAIR-facility<br />

will provide heavy ion beams of highest intensities.<br />

Ionization beam loss is the most important loss<br />

mechanism at operation with high intensity,<br />

intermediate charge state heavy ions. A special<br />

synchrotron design has been developed for SIS100,<br />

aiming for hundred percent control of ionization<br />

beam loss by means of a dedicated cold ion catcher<br />

system. To suppress dynamic vacuum effects, the<br />

cryo catcher system shall also provide a significantly<br />

reduced effective desorption yield. The construction<br />

and tests of a prototype cryo ion catcher is a work<br />

package of the EU-FP-7 project COLMAT. A<br />

prototype test setup including cryostat has been<br />

constructed, manufactured and tested at GSI under<br />

realistic conditions with heavy ion beams of the of<br />

the heavy ion synchrotron SIS18. The design and<br />

results are presented.<br />

Funding Agency EU-FP-7 project COLMAT, FIAS<br />

Sub Classification: T14 Vacuum Technology<br />

Poster Panel 115<br />

ID: 3149 - TUPS023<br />

Secondary Electron Yield on Cryogenic Surfaces<br />

as a Function of Physisorbed Gases,<br />

Asena Kuzucan, Holger Neupert, Mauro Taborelli<br />

(CERN, Geneva), Herbert Stoeri (IAP TUW, Wien)<br />

- Electron cloud is a serious limitation for the<br />

operation of particle accelerators with intense<br />

beams. It occurs if the metal surface secondary<br />

electron yield (SEY) is sufficiently high to promote<br />

electron multiplication. At low surface temperature<br />

SEY is strongly influenced by the nature of the<br />

physisorbed gases and by the corresponding surface<br />

coverage. These conditions occur in many<br />

accelerators operating with superconducting<br />

magnets and cold vacuum sections as for instance<br />

LHC. In this work we investigated the variation of<br />

secondary electron yield of copper, aluminium and<br />

electro polished copper as a function of physisorbed<br />

N2, CO, CO2, CH4, Kr, C2H6 at cryogenic<br />

temperatures. Conditioning of after physisorption of<br />

H2O on electro polished copper will also be<br />

presented. The results of the various gases are


compared in order to find a rationale for the<br />

behaviour of the secondary electrons for various<br />

adsorbates.<br />

Sub Classification: T14 Vacuum Technology<br />

Poster Panel 116<br />

ID: 3356 - TUPS014<br />

Vacuum Performance Simulation of C-band<br />

Accelerating Structures, Huijea Lee, Moo-Hyun<br />

Cho, Sang-Hoon Kim, Changho Yi (POSTECH,<br />

Pohang, Kyungbuk), Won Namkung, Chong-Do<br />

Park (PAL, Pohang, Kyungbuk) - A C-band<br />

accelerating structure has a higher accelerating<br />

gradient than that of the S-band structure. It provides<br />

a good benefit of a shorter machine length. In order<br />

to effectively use RF power and for cost reduction,<br />

the accelerating structure should be as long as<br />

possible. We propose a 2.2-m long structure<br />

compared to 1.8-m at XFEL/SPring-8. However,<br />

longer accelerating structure has worse vacuum<br />

performance than shorter accelerating structure.<br />

Thus, vacuum conductance of 2.2-m long structure<br />

has to be checked. We calculate vacuum<br />

performance of accelerating structure by analytical<br />

method and FEM. In this paper, we present that the<br />

vacuum performance for the 2.2-m long accelerating<br />

structure is safe enough for the XFEL LINAC.<br />

Funding Agency: This work is partly supported by<br />

the MEST and POSTECH Physics BK21 program.<br />

Sub Classification: T14 Vacuum Technology<br />

Poster Panel 117<br />

ID: 4032 - TUPS028<br />

Performance of Amorphous Carbon Coating for<br />

the Mitigation of Electron Cloud in the SPS,<br />

Christina Yin Vallgren, Paolo Chiggiato, Pedro<br />

Costa Pinto, Holger Neupert, Giovanni Rumolo,<br />

Elena Shaposhnikova, Mauro Taborelli (CERN,<br />

Geneva) - Amorphous carbon (a-C) coatings have<br />

been tested in electron cloud monitors (ECM) in the<br />

Super Proton Synchrotron (SPS) and have shown for<br />

LHC type beams a reduction of the EC current by a<br />

factor 10E4 compared to stainless steel (SS). This<br />

performance has been maintained for more than 2<br />

years under SPS operation conditions. Secondary<br />

electron yield (SEY) laboratory data confirm that<br />

after 1 year of SPS operation, the coating maintains<br />

a SEY below 1. The compatibility of coexisting SS<br />

and a-C surfaces has been studied in an ECM having<br />

coated and uncoated areas. The results show no<br />

degradation of the properties of the a-C areas. The<br />

performance of diamond like carbon (DLC) coating<br />

has also been studied. DLC shows a less effective<br />

�<br />

34<br />

reduction of the EC current than a-C, but<br />

conditioning is faster than for SS. Three a-C coated<br />

dipoles were inserted in the SPS. However, even<br />

with no EC detected, the dynamic pressure rise is<br />

similar to the one observed in the SS reference<br />

dipoles. Measurement in a new ECM equipped with<br />

clearing electrodes to verify the relation between<br />

pressure signals and intensity of the EC, as well as<br />

an improvement of the diagnostics in the dipoles are<br />

in progress.<br />

Sub Classification: T14 Vacuum Technology<br />

Poster Panel 118<br />

ID: 3813 - TUPS037<br />

Preliminary Assessment of Beam Impact<br />

Consequences on LHC Collimators,<br />

Marija Cauchi, Ralph Assmann, Alessandro<br />

Bertarelli, Roderik Bruce, Federico Carra,<br />

Alessandro Dallocchio, Daniel Deboy, Nicola<br />

Mariani, Adriana Rossi (CERN, Geneva), Luisella<br />

Lari (CERN, Geneva; IFIC, Valencia), Nicholas<br />

Sammut (CERN, Geneva; University of Malta,<br />

Msida), Pierluigi Mollicone (UoM, Msa) - The<br />

correct functioning of the LHC Collimation System<br />

is crucial to attain the desired LHC luminosity<br />

performance. However, the requirements to handle<br />

high intensity beams can be demanding. In this<br />

respect, the robustness of the collimators plays an<br />

important role. An accident which causes the proton<br />

beam to hit a collimator might result in severe beaminduced<br />

damage and, in some cases, replacement of<br />

the collimator, with consequent downtime for the<br />

machine. In this paper, several case studies<br />

representing different realistic beam impact<br />

scenarios will be shown. A preliminary analysis of<br />

the thermo-mechanical response of several<br />

collimators to beam impact will be presented, from<br />

which the most critical cases can then be identified.<br />

Such work will also help to give an initial insight on<br />

the operational constraints of the LHC by taking into<br />

account all relevant collimator damage limits.<br />

Sub Classification: T19 Collimation<br />

Poster Panel 119<br />

ID: 4557 - TUPS044<br />

Recent Developments on the IFMIF/EVEDA<br />

Beam Dump Cooling Circuit, Marcos Parro,<br />

Fernando Arranz, Beatriz Brañas, Daniel Iglesias,<br />

David Rapisarda (CIEMAT, Madrid) - During the<br />

IFMIF/EVEDA activities a conical dump made of<br />

copper has been designed to stop the 125 mA, 9<br />

MeV, D+ beam. This element will receive a total<br />

power of ~1 MW. It is cooled by a high velocity


water flow that circulates through an annular<br />

channel along the outer surface of the cone. The<br />

coolant composition must be defined taking into<br />

account corrosion and erosion phenomena. Also, as<br />

important neutron and gamma fluxes are generated<br />

in the beam stop, the activation of corrosion<br />

products and the water radiolysis must be<br />

considered. During commissioning of the<br />

accelerator, pulsed beams with low duty cycle will<br />

be used and therefore the power will be significantly<br />

lower than the nominal one. With the double aim of<br />

minimizing erosion and of reproducing the full<br />

power margin to local boiling (used as safety<br />

interlock) it is planned to use flows lower than the<br />

nominal one. This work will present the different<br />

operation scenarios and the coolant composition<br />

choice performed.<br />

Sub Classification: T20 Targetry<br />

Poster Panel 120<br />

ID: 3131 - TUPS070<br />

An Experiment at HiRadMat: Irradiation of<br />

High-Z Materials, Juan Blanco, Ruediger Schmidt<br />

(CERN, Geneva), Naeem A. Tahir (GSI, Darmstadt)<br />

- Calculations of the impact of dense high intensity<br />

proton beams at SPS and LHC into material have<br />

been presented in several papers*,**,***. This paper<br />

presents the plans for an experiment to validate the<br />

theoretical results with experimental data. The<br />

experiment will be performed at the High Radiation<br />

to Materials (HiRadMat) facility at the CERN-SPS.<br />

The HiRadMat facility is dedicated to shock beam<br />

impact experiments. It allows testing of accelerator<br />

components with respect to the impact of highintensity<br />

pulsed beams. It will provide a 440 GeV<br />

proton beam with a focal size down to 0.1 mm, thus<br />

providing very dense beam (energy/cross section).<br />

The transversal profile of the beam is considered to<br />

be Gaussian with a tunable sigma from 0.1 mm to 2<br />

mm. This facility will allow to study “high energy<br />

density” physics as the energy density will be high<br />

enough to create strong coupled plasma in the core<br />

of high-Z materials (copper, tungsten) and to<br />

produce strong enough shock waves to create a<br />

density depletion channel along the beam axis<br />

(tunneling effect). The paper introduces the layout of<br />

the experiment and the monitoring system to detect<br />

tunneling of protons through the target.<br />

* N.A.Tahir et al. HB2010 Proc., Morschach,<br />

Switzerland.<br />

** N.A.Tahir et al. NIMA 606(1-2) 2009 186.<br />

*** N.A.Tahir et al. 11th EPAC, Genoa, Italy, 2008,<br />

WEPP073.<br />

�<br />

35<br />

Sub Classification: T23 Machine Protection<br />

Poster Panel 121<br />

ID: 4489 - MOPC148<br />

MedAustron Timing System and MRF Timing<br />

Equipment Upgrade, Rok Tavcar, Rok Stefanic,<br />

Igor Verstovsek (Cosylab, Ljubljana) - MedAustron<br />

is a new ion beam therapy and research centre under<br />

construction in Wiener Neustadt, Austria. The<br />

timing system for its synchrotron particle accelerator<br />

is being developed in close collaboration between<br />

MedAustron and Cosylab. We have chosen Micro<br />

Research Finland (MRF) timing equipment as the<br />

transfer layer platform and redesigned the FPGA<br />

firmware on both the master and the receiver in<br />

order to address machine specific requirements<br />

which exceed MRF's original capabilities. Being<br />

involved in MedAustron control system design both<br />

vertically and horizontally has enabled us to create a<br />

timing system transport layer that meets the<br />

demands of this class of compact accelerators<br />

intended for clinical use. We have achieved it while<br />

maintaining generality – the main characteristic of<br />

MRF timing equipment that led to its de-facto<br />

standard status seen today. Added functionalities<br />

include a flexible event response mechanism on the<br />

receiver side and support for virtual accelerators -<br />

concurrently operating accelerator partitions. This<br />

article explains the timing system design overview<br />

with emphasis on its main conceptual specifics<br />

requiring the redesign of MRF firmware.<br />

Sub Classification: T24 Timing and<br />

Synchronization<br />

Poster Panel 122<br />

ID: 2831 - TUPS094<br />

Research of Thermal Deformation on a Compact<br />

Cyclotron CYCHU-10, Kaifeng Liu (HUST,<br />

Wuhan) - Nowadays, a cyclotron CYCHU-10 used<br />

for PET is under construction in Huazhong<br />

University of Science and Technology (HUST) due<br />

to the growing demands in medical applications. For<br />

space-saving and low energy consumption, the<br />

CYCHU-10 was designed compactly and accurately,<br />

especially for the RF cavity consists of the valley of<br />

the magnetic pole and the dee electrodes installed on<br />

the vacuum chamber. The RF system will supply a<br />

10kw power and large part of it will transform into<br />

thermal energy.This paper will introduce the thermal<br />

deformation of the RF cavity and the main vacuum<br />

chamber. Meanwhile the finite elements analysis<br />

thermal deformation with ANSYS Products will be<br />

present.Finally, the cooling system for the RF cavity


will be carefully designed due to the result of thermo<br />

analysis and the mechanical tolerance demand in the<br />

RF system. Keywords- thermal deformation;<br />

mechanical tolerance; FEA;RF power.<br />

Sub Classification: T30 Subsystems, Technology<br />

and Components, Other<br />

Poster Panel 123<br />

ID: 1747 - TUPS082<br />

Low Energy Bunching with a Double Gap RF<br />

Buncher, Heinrich von Jagwitz, Ulrich Hagen,<br />

Oliver Heid, Stefan Setzer (Siemens AG, Erlangen)<br />

- A compact double gap bunching system for low<br />

energy proton beams is presented. The system is<br />

designed for the bunching of a low current proton<br />

beam (less than 50μA) with an energy of 10 keV.<br />

The buncher operates at 150 MHz and bunches<br />

without significantly changing the beam energy. The<br />

�<br />

36<br />

beam is generated by an Electron Beam Ion Source<br />

and has to be bunched for the subsequent<br />

acceleration in a 150 MHz linear accelerator. The<br />

buncher contains two short gaps and an RF electrode<br />

inbetween. Thus the full length of the buncher in the<br />

beamline is in the range of 2 cm. The location of the<br />

bunch focus depends on the buncher power. The<br />

bunched beam was analysed at a distance of 550 mm<br />

with a fast faraday cup. The bunching effectivity<br />

was determined as 50%, which means that 50% of<br />

the protons of the beam were located in bunches<br />

with a width of 60°, which is a reasonable value of<br />

acceptance for a conventional accelerator cavity.<br />

Some theory and detailed results will be presented.<br />

Sub Classification: T30 Subsystems, Technology<br />

and Components, Other


�<br />

Main Classification 8: Applications of <strong>Accelerator</strong>s<br />

Poster Panel 124<br />

ID: 3215 - THPS082<br />

Design Choices of the MedAustron Nozzles and<br />

Proton Gantry based on Modeling of <strong>Particle</strong><br />

Scattering, Marcus Palm (ATI, Wien; CERN,<br />

Geneva), Michael Benedikt (CERN, Geneva; EBG<br />

MedAustron, Wr. Neustadt), Adrian Fabich (EBG<br />

MedAustron, Wr. Neustadt) - MedAustron, the<br />

Austrian hadron therapy center is currently under<br />

construction. Irradiations will be performed using<br />

active scanning with a pencil beam. For applications<br />

where sharp lateral beam penumbras are required to<br />

spare critical organs from undesired dose exposure,<br />

an important factor is scattering in e.g. beam<br />

monitors, air and vacuum windows - particularly for<br />

low-energy proton beams. A semi-empirical<br />

scattering model has been established to evaluate<br />

beam growth due to scattering in the proton gantry<br />

and fixed beam line irradiation rooms. Major design<br />

choices for proton gantry and nozzle based on the<br />

scattering calculations are presented.<br />

Sub Classification: U01 Medical Applications<br />

Poster Panel 125<br />

ID: 3405 - THPS091<br />

Development of the Pulse Radiolysis System with<br />

a Supercontinuum Radiation using Photonic<br />

Crystal Fiber, Koichi Ogata, Ryosuke Betto [on<br />

leave], Yuji Hosaka [on leave], Yohei Kawauchi [on<br />

leave], Kazuyuki Sakaue [on leave], Tatsuya Suzuki<br />

[on leave], Masakazu Washio [on leave] (RISE,<br />

Tokyo), Ryunosuke Kuroda [on leave] (AIST,<br />

Tsukuba, Ibaraki), Shigeru Kashiwagi [on leave]<br />

(Tohoku University, Sendai) - In usage of radiation,<br />

it is important to study the process of chemical<br />

effects of ionizing radiation in a material. Pulse<br />

radiolysis is a method to trace these rapid initial<br />

chemical reactions by ionizing radiation. As a pump<br />

beam, we are using 5MeV electron beam produced<br />

from the S-band photo cathode RF-Gun. In<br />

nanosecond timescale pulse radiolysis, it is required<br />

the stable probe light of a broad spectrum. And<br />

especially in picosecond timescale pulse radiolysis,<br />

probe light should have short pulse width to use<br />

stroboscopic method. Therefore, in order to develop<br />

a wide range of timescale experimental system, we<br />

have been developing a Supercontinuum (SC) light<br />

as a probe light, which is generated by nonlinear<br />

optical process of short pulse IR laser in photonic<br />

crystal fiber (PCF). As a result, the SC light<br />

37<br />

spectrum is broad enough to use as a probe light.<br />

Then we tried to measure the absorption spectrum of<br />

hydrated electron by SC light, we successfully<br />

observed good signal-noise ratio data both<br />

nanosecond and picosecond experiment with unified<br />

pulse radiolysis system. In this conference, we will<br />

report details of these results and future prospects.<br />

Funding Agency: Work supported by JSPS Grant-in-<br />

Aid for Scientific Research (A) 10001690<br />

Sub Classification: U02 Materials Analysis and<br />

Modification<br />

Poster Panel 126<br />

ID: 2872 - THPS098<br />

Neutron–physical Characteristics of the<br />

Subcritical Setup with Natural Uranium Blanket<br />

Bombarded by Deuterons with Energy 4 GeV,<br />

Maryna Artiushenko, Yuri Petrusenko, Vladimir<br />

Sotnikov, Vladimir Voronko (NSC/KIPT, Kharkov),<br />

Andrei Patapenka, Anastasiya Safronava, Igor Zhuk<br />

(JIPNR-Sosny NASB, Minsk) - An extended U/Pbassembly<br />

was irradiated with an extracted beam of 4<br />

GeV deuterons from the Nuclotron accelerator at the<br />

JINR, Dubna, Russia. Information on the spatial<br />

distributions of neutrons in the lead target and the<br />

uranium blanket was obtained with sets of activation<br />

detectors (natPb and natU) and solid state nuclear<br />

track detectors (SSNTD). Spatial distribution of the<br />

natPb, and natU fission reaction rates in the volume<br />

of the target and blanket installation were obtained<br />

using SSNTD techniques. Activation method was<br />

used to obtain the spatial distributions of 238U(n,g),<br />

238U(n,f) reactions rates. The procedure of<br />

combining the track counting and gammaspectrometry<br />

techniques for the determination of<br />

spectral indices is a new development. It includes<br />

gathering information from the same sample by<br />

SSNTD methods, i.e., counting the fission tracks of<br />

238U, and also by gamma-spectrometry of 239Np<br />

production. Sets of spectral indices values (ratio of<br />

238U(n,g) to 238U(n,f) reaction rates), representing<br />

the integral nuclear data were defined. Comparison<br />

between the experimental data and the calculations<br />

performed with the use of the computer numerical<br />

code FLUKA2008 was made.<br />

Sub Classification: U03 Transmutation and Power<br />

Generation


Poster Panel 127<br />

ID: 2930 - THPS104<br />

Novel Schemes for the Narrow Band Sparc THz<br />

Source using a Comb-like e-beam,<br />

Barbara Marchetti (INFN-Roma II, Roma),<br />

Concetta Ronsivalle (ENEA C.R. Frascati, Frascati<br />

(Roma)), Manuela Boscolo, Michele Castellano,<br />

Enrica Chiadroni, Massimo Ferrario, Bruno Spataro,<br />

Cristina Vaccarezza (INFN/LNF, Frascati (Roma)),<br />

Alessandro Cianchi (Università di Roma II Tor<br />

Vergata, Roma) - The development of radiation<br />

sources in the THz spectral region has become more<br />

and more interesting because of the peculiar<br />

characteristics of this radiation: it is non ionizing, it<br />

penetrates dielectrics, it is highly absorbed by polar<br />

liquids, highly reflected by metals and reveals<br />

�<br />

38<br />

specific "fingerprint" absorption spectra arising from<br />

fundamentals physical processes. The THz source at<br />

SPARC is an accelerator based source for research<br />

investigations (e.g. material science, biology fields).<br />

By means of e-beam manipulation technique, a<br />

longitudinal modulated beam, the so-called comb<br />

beam, can be produced at Sparc. In terms of THz<br />

sources, such e-beam distribution allows to produce<br />

high intensitiy narrow band THz radiation, whose<br />

spectrum strongly depends on the charge distribution<br />

inside the e-beam. Different linac schemes are<br />

compared. In particular, spectra obtained using the<br />

comb-beam compression through velocity bunching<br />

including a IV harmonic RF section is showed.<br />

Sub Classification: U05 Other Applications


�<br />

Post Deadline Inclusion in Student Poster Session<br />

In Classifications 02 and 07<br />

Poster Panel 128<br />

Classification 02 Synchrotron Light Sources and<br />

FELs/T02 Lepton Sources<br />

ID: 3953 - THPC117<br />

Analysis Quantum Efficiency Spectrum of NEA-<br />

GaAs Photocathode, Yuki Masumoto (HU/AdSM,<br />

Higashi-Hiroshima) - ERL is a future project of<br />

synchrotron light source with high brightness and<br />

partial coherence. ERL is based on super conducting<br />

linear accelerator providing the high brightness<br />

electron beam to insertion devices continuously.<br />

One of the most difficult technical challenge is the<br />

electron source for ERL. A photo-cathode DC<br />

biased gun is assumed, but several issues should be<br />

solved. One of the issue is the operational lifetime of<br />

cathode material, NEA GaAs. NEA stands for<br />

Negative electron affinity made by artificial<br />

treatment on clean GaAs surface. Emission from the<br />

cathode is decreased in time and extracted beam<br />

current. In order to research the phenomena, the<br />

surface potential is studied by measuring the QE<br />

(Quantum Efficiency) spectrum. Observing temporal<br />

evolution of QE, we found that the photon energy<br />

threshold did not change during the decay. The<br />

spectrum shape was changed suggesting that the<br />

surface potential barrier becomes thicker.<br />

39<br />

Poster Panel 129<br />

Classification 07 <strong>Accelerator</strong> Technology/T07<br />

Superconducting RF<br />

ID: 3322 - MOPC102<br />

RF and Surface Properties of Superconducting<br />

Samples, Tobias Junginger (CERN, Geneva;<br />

MPI-K, Heidelberg), Wolfgang Weingarten<br />

(CERN, Geneva), Carsten Peter Welsch (Cockcroft<br />

Institute, Warrington, Cheshire; The University of<br />

Liverpool, Liverpool), Rebecca Seviour (Lancaster<br />

University, Lancaster) - The surface resistance Rs of<br />

superconducting cavities can be obtained from the<br />

unloaded quality factor Q0. Since Rs varies strongly<br />

over the cavity surface its value must be interpreted<br />

as averaged over the whole cavity surface. A more<br />

convenient way to investigate the surface resistance<br />

of superconducting materials is therefore to examine<br />

small samples, because they can be manufactured<br />

cheaply, duplicated easily and used for further<br />

surface analyses. At CERN a compact Quadrupole<br />

Resonator has been developed for the RF<br />

characterization of superconducting samples at<br />

different frequencies. In this contribution, results<br />

from measurements on bulk niobium and niobium<br />

film on copper samples are presented. It is shown<br />

how different contributions to the surface resistance<br />

depend on temperature, applied RF magnetic field<br />

and frequency. Furthermore, measurements of the<br />

maximum RF magnetic field as a function of<br />

temperature and frequency in pulsed and CW<br />

operation are presented. The study is accompanied<br />

by measurements of the surface properties of the<br />

samples by various techniques.<br />

Work supported by the German Doctoral Students<br />

program of the Federal Ministry of Education and<br />

Research (BMBF)

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