| Paper |
Title |
Page |
| TUP048 |
Beam-Loading Effect in the Normal-Conducting ILC Positron Source Pre-Accelerator
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355 |
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- V. V. Paramonov
RAS/INR, Moscow
- K. Floettmann
DESY, Hamburg
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Significant positron bunch charge (several nC) in the ILC Positron Source results in high pulse beam loading for normal-conducting accelerating structures in Positron Pre-Accelerator (PPA). Time interval between bunches (~ 300 ns) is not negligibly small in comparison with accelerating structure time constant (rise time for Standing Wave (SW) or filling time for Traveling Wave (TW) options). As the result, beam loading effect has particularities both from stored energy acceleration regime and continuous beam loading one. Taking into account particular PPA beam structure, beam loading effect is estimated for the present ILC base line parameters, both for SW and TW PPA options. Possible solutions for beam loading compensation are discussed.
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| THP033 |
Pulsed RF Heating Particularities in Normal-Conducting L-band Cavities
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646 |
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- V. V. Paramonov, A. K. Skasyrskaya
RAS/INR, Moscow
- K. Floettmann
DESY, Hamburg
- F. Stephan
DESY Zeuthen, Zeuthen
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For present projects, such as X-FEL and ILC, the SC technology is chosen for the main linacs. However, in some special parts, NC cavities are applied, operating with high electric and magnetic fields. RF gun cavities with an electric field up to 60 MV/m at the photo cathode are now under development. Capture cavities in the ILC positron source should operate with an accelerating gradient of up to 15 MV/m, practically the same value (14 MV/m), as for the CDS booster cavity in the Photo Injector Test Facility at DESY in Zeuthen (PITZ). High field strength leads to high specific RF heat loading. In combination with long RF pulses (~ 1ms) it results in substantial surface temperature rise, small cavity shape deformations and measurable frequency shifts. In this report we discuss both particularities and some general regularities related to long pulse operation of L-band cavities. Results of 3D numerical simulations for cavity surface temperature, displacements distributions and corresponding frequency shifts for different cavities are presented and compared with existing experimental data. The presented results will give the input for cavities optimization and sub-systems improvements.
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| THP034 |
Effective Standing-Wave RF Structure for Charged-Particle Beam Deflector
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649 |
| |
- V. V. Paramonov, L. V. Kravchuk
RAS/INR, Moscow
- S. A. Korepanov
DESY Zeuthen, Zeuthen
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In this report we describe new standing wave pi-mode rf structure for charged particles deflection. For L-band frequency range parameters of the proposed structure are compared with classical TM110 mode deflecting cavity ones. With originating TE11n mode, our proposal has several times higher rf efficiency, one order wider pass-band and smaller (in times) transverse dimensions. The cavity design idea and typical are parameters are presented. Some particularities of the beam dynamics in the proposed structure are pointed out. Preferable field of structure application is discussed.
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| THP063 |
First High-Power ACS Module for J-PARC Linac
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725 |
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- H. Ao, K. Hasegawa, K. Hirano, T. Morishita, A. Ueno
JAEA/LINAC, Ibaraki-ken
- M. Ikegami
KEK, Ibaraki
- V. V. Paramonov
RAS/INR, Moscow
- Y. Yamazaki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
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J-PARC Linac will be commissioned with energy of 181-MeV using 50-keV ion source, 3-MeV RFQ, 50-MeV DTL and 181-MeV SDTL (Separated DTL) on December 2006. It is planed to be upgraded by using 400-MeV ACS (Annular Coupled Structure), in a few years from the commissioning. The first high-power ACS module, which will be used as the first buncher between the SDTL and the ACS has been fabricated, and a few accelerating modules are also under fabrication until FY2006. Detail of cavity design and tuning procedure has been studied with RF simulation analysis and cold-model measurements. This paper describes RF measurement results, fabrication status, and related development items.
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