Abstracts Brochure - 2nd International Particle Accelerator Conference
Abstracts Brochure - 2nd International Particle Accelerator Conference
Abstracts Brochure - 2nd International Particle Accelerator Conference
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
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)