| Paper |
Title |
Other Keywords |
Page |
| MOPKF067 |
Comparison of Different Buncher Cavity Designs for the 4GLS ERLP
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gun, linac, emittance, space-charge |
467 |
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- E. Wooldridge, C.D. Beard, C. Gerth
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- A. Buechner
FZR/FWFE, Dresden
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A DC photocathode gun is part of the injector of the Energy Recovery Linac Prototype (ERLP) currently built at Daresbury Laboratory. A buncher is required for the ERLP to decrease the bunch length off the gun. Three different single-cell cavity designs were investigated: The Cornell buncher, the Elbe Buncher and an EU cavity without Higher Order Mode (HOM) dampers. The properties of these cavities were studied with the computer codes CST's Microwave Studio and ASTRA. The fundamental frequency and field pattern was investigated in Microwave Studio. The EU cavity had to be scaled from 500MHz as the required frequency for the buncher is 1.3GHz. As the anticipated kinetic energy of the electron beam after the gun is about 350keV a particle tracking code including the space charge forces is mandatory to study the effect of the different buncher cavity designs on the beam dynamics. The particle tracking code ASTRA was used to study the performance of the bunchers for a variety of beam parameters. From these investigations it was found that the three bunchers produce very similar effects on the particle bunch.
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| MOPLT133 |
Beam Loading and Higher-band Longitudinal Wakes in High Phase Advance Traveling Wave Accelerator Structures for the GLC/NLC
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beam-loading, impedance, simulation, linear-collider |
848 |
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- R.M. Jones, V.A. Dolgashev, Z. Li, T.O. Raubenheimer
SLAC, Menlo Park, California
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A multi-bunch beam traversing traveling wave accelerator structures, each with a 5pi/6 phase advance is accelerated at a frequency that is synchronous with the fundamental mode frequency. As per design, the main interaction occurs at the working frequency of 11.424 GHz. However, modes with frequencies surrounding the dominant accelerating mode are also excited and these give rise to additional modal components to the wakefield. Here, we consider the additional modes in the context of X-band accelerator structures for the GLC/NLC (Global Linear Collider/Next Linear Collider). Finite element simulations, mode-matching and circuit models are employed in order to calculate the wakefield.
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| THPLT014 |
Coupler Structures for the LHC Beam-pipe Waveguide Mode Reflectometer
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coupling, vacuum, simulation, dipole |
2493 |
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- T. Kroyer
TU Vienna, Vienna
- F. Caspers
CERN, Geneva
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The LHC reflectometer will be used to detect and localize obstacles and other kinds of discontinuities in the LHC beam screen. An important part of this device is the RF coupler element, which provides the interface between the circular beam screen and the measurement equipment. Two different scenarios of operation are considered. The first option consists in carrying out measurements during assembly by directly branching a coupler to the end of the beam screen. The other one is a permanent installation to be used in situ requiring a different kind of coupler to keep the aperture free. The goal is to achieve a reasonably well-matched spurious mode-free excitation over a 25% bandwidth for the TM01 and the T·1011 mode, respectively. The fulfillment of the required features is severely complicated by space and material restrictions arising mainly from vacuum and installation constraints.
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