Abstracts Brochure - 2nd International Particle Accelerator Conference

First, we develop a model describing this interaction
and then we supplement it with numerical results
using PIC code WARP***. We show that the ions
move towards the area occupied by the dark current,
but this does not increase the bombardment of
micro-protrusions.
* R.B. Palmer,et al, Phys. Rev ST Accel. Beams 12,
031002 (2009).
** P. Wilson, AIP Conf. Proc., 877, Melville, New
York, 2006, p. 27.
*** J.-L. Vay, et al, Physics of Plasmas, 11, 2928
(2004).
Funding Agency: This work is supported by Office
of High Energy Physics of the U.S. Department of
Energy.
Sub Classification: T06 Room Temperature RF
Poster Panel 100
ID: 4471 - MOPC066
Role of Nottingham and Thomson Effects in
Heating of Micro-protrusion in High-gradient
Accelerating Structures, Aydin Cem Keser, Tom
Antonsen, Dmytro Kashyn, Gregory Nusinovich
(UMD, College Park, Maryland) - It is widely
accepted that one of the reasons for appearance of
the RF breakdown which limits operation of highgradient
accelerating structures is the electron dark
current*. This field emitted current, usually
considered as a precursor of the breakdown, can be
emitted from apexes of microprotrusions on a
structure surface. Therefore field and thermal
processes in such protrusions deserve careful
studies**. The goal of our first study*** was to
analyze 2D process of RF field penetration inside
protrusion of a metal with finite conductivity and to
study corresponding Joule heating. In the present
study, we include into consideration, first, the
Nottingham effect which may significantly change
the protrusion heating. Then, since protrusion
heating in high-power, short-pulse operation can be
strongly non-uniform, we include into consideration
also Thomson effect which predicts additional
heating/cooling in non-uniformly heated conductors.
* Wang and Loew, SLAC-pub-7684,1997
** K.L.Jensen,Y.Y. Lau, D.W. Feldman, P.G.
O'Shea, Phys. Rev. ST Accel.Beams 11,
081001(2008)
*** Kashyn et al, AAC-2010.
Sub Classification: T06 Room Temperature RF
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30
Poster Panel 101
ID: 3159 - MOPC022
Development of a Compact C-band Photocathode
RF Gun, Xiaohan Liu, Chuanxiang Tang (TUB,
Beijing) - A C-band photocathode RF gun for a
compact electron diffraction facility is developed in
Tsinghua University, which is designed to work at
the frequency of 5.712GHz. This paper presents the
physics and structure design of this C-band RF gun,
and the comparison on beam dynamics of S-band
and C-band photoinjector has been done. Some new
structure design will be adopted in this gun,
including the optimized cavity length and elliptical
iris, which is helpful to achieve lower emittance and
larger mode separation. This paper likewise presents
experiment parameters and the preliminary cold test
results of this C-band RF gun.
Funding Agency This work is supported by
National Natural Science Foundation of China and
National Basic Research Program of China (973
Program).
Sub Classification: T06 Room Temperature RF
Poster Panel 102
ID: 1866 - MOPC026
A-core Loaded Untuned RF Compression Cavity
for HIRFL-CSR, Lirong Mei, Zhe Xu, Youjin
Yuan, Hongwei Zhao (IMP, Lanzhou) - To meet the
requirement of conducting high energy density and
plasma physics research at HIRFL-CSR. The higher
accelerating gap voltage was required. A magnetic
alloy (MA)-core loaded radio frequency (RF) cavity
which can provide higher accelerating gap voltage
has been studied in Institute of Modern Physics,
Chinese Academy of Sciences (IMP, CAS),
Lanzhou. To select proper MA material to load the
RF compression cavity, measurement for MA cores
has been conducted. The MA core with higher
permeability and shunt impedance, and lower
quality factor (Q value) should be selected. The
theoretical calculation and simulation for the MAcore
loaded RF cavity can be consistent with each
other well. Finally 230kW power was needed to
meet 50-kV accelerating gap voltage by calculation.
Sub Classification: T06 Room Temperature RF
Poster Panel 103
ID: 3198 - MOPC040
The Measurement of Transversal Shunt
Impedance of RF Deflector, Aleksandr Smirnov,
Michael Vladimirovich Lalayan, Nicolay Sobenin
(MEPhI, Moscow), Aleksandr Alekseevich
Zavadtsev (Nano, Moscow) - This paper presents the