
Contributions to IPAC98
September 1418, Monterey, CA

This page compiles contributions to the ICAP98 conference (International
Computational Accelerator Physics Conference ) from the accelerator
R&D group for the JLC. Some papers, which are not written by the
group members, but are considered relevant or interesting, are also
included. For full listing of all the papers at ICAP98, go to
http://www.slac.stanford.edu/xorg/icap98/.
LTu20  Design of 2×2 DLDS RF Components for JLC
 Authors: J.Q.Wang et al
 Abstract:
We have studied a multimode Delay Line Distribution
System (DLDS) as the RF power distribution
system from klystrons to RF structures for linear
colliders. In particular, a 22×2 DLDS has been proposed
and studied at KEK for Japan Linear Collider(JLC). It has
been proved that the 22×2 DLDS is simple, bus has good
transmission efficiency. We have designed RF
components of a basic unit of a DLDS using the High
Frequency Structure Simulator (HFSS) code[3]. They
include the TE01 extractor, the TE11 to TE01 converter, and
the TE11 to TE12 converter for TE12 mode. HFSS
calculation of the system, which consists of TE01 extractor
and TE11 to TE01 converter, shows that the transmission
efficiency of each mode is better than 95%. A low power
test model for the mode stability experiment in 55m long
wave guide in DLDS is also being developed. Further
study is underway.
 Download:
PDF file
STh04  New Method for Klystron Modelling
 Authors: Y.H.Chin
 Abstract:
We have developed a new method for a realistic and more
accurate simulation of klystron using the MAGIC code.
MAGIC is the 2.5D or 3D, fully electromagnetic and
relativistic particleincell code for selfconsistent
simulation of plasma. It solves the Maxwell equations in
time domain at particle presence for a given geometrical
structure. It uses no model or approximation for the beamcavity
interaction, and thus keeps all physical processes
intact. With MAGIC, a comprehensive, fullscale
simulation of klystron from cathode to collector can be
carried out, unlike other codes that are specialized for
simulation of only parts of klystron. It has been applied
to the solenoidfocused KEK XB72K No.8 and No.9
klystrons, the SLAC XL4 klystron, and the BINP PPM
klystron. Simulation results for all of them show good
agreements with measurements. We have also developed a
systematic design method for high efficiency and low
gradient travelingwave (TW) output structure. All these
inventions were crystallized in the design of a new
solenoidfocused XB72K No.10. Its predicted performance
is 126 MW output power (efficiency 48.5%) with peak
surface field of about 77 MV/m, low enough to sustain a
1.5 μs long pulse. It is now in manufacturing and testing
is scheduled to start from December 1998.
 Download:
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CTh12  Calculations of the ShortRange Longitudinal Wakefields in the
NLC Linac
 Authors: K.Bane, A.Mosnier, A.Novakhatski and K.Yokoya
 Abstract:
Using two frequency domain and one time domain numerical
approaches, we calculate the shortrange longitudinal
wakefield of the NLC linac accelerating structure, and find
that the results agree to ~5%. We show that our results
are consistent with an analytical formula for the impedance
at high frequencies. We, in addition, obtain through fitting
a simple formula for the shortrange wakefield of a linac
structure that can be useful in designing linear colliders.
Finally, we demonstrate that for the NLC linac cavity the
effects on the shortrange wake of end conditions, tapering,
and rounding of the irises are small.
 Download:
PDF file
Last modified: Sat Jul 16 20:23:46 JST 2005