Paper |
Title |
Other Keywords |
Page |
MOPCH118 |
Wideband Low-output-impedance RF System for the Second Harmonic Cavity in the ISIS Synchrotron
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impedance, synchrotron, controls, acceleration |
321 |
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- Y. Irie
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- D. Bayley, G.M. Cross, I.S.K. Gardner, M.G. Glover, D. Jenkins, A. Morris, A. Seville, S.P. Stoneham, J.W.G. Thomason, T. Western
CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
- J.C. Dooling, D. Horan, R. Kustom, M.E. Middendorf, G. Pile
ANL, Argonne, Illinois
- S. Fukumoto, M. Muto, T. Oki, A. Takagi, S. Takano
KEK, Ibaraki
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Wideband low-output-impedance RF system for the second harmonic cavity in the ISIS synchrotron has been developed by the collaboration between Argonne National Laboratory, US, KEK, Japan and Rutherford Appleton Laboratory, UK. Low output impedance is realized by the feedback from plate output to grid input of the final triode amplifier, resulting in less than 30 ohms over the frequency range of 2.7 - 6.2 MHz which is required for the second harmonic cavity. The vacuum tubes in the driver and final stages are both operated in class A, and a grid bias switching system is used on each tube to avoid unnecessary plate dissipations during a non-acceleration cycle. High power test was performed with a ferrite-loaded second harmonic cavity, where the bias current was swept at 50 Hz repetition rate. The maximum voltage of 12kV peak per accelerating gap was obtained stably at earlier period of an acceleration cycle. A beam test with this system is planned at the ISIS synchrotron in order to investigate how the low impedance system works under heavy beam loading conditions, and is capable of mitigating the space charge detuning at the RF trapping stage.
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MOPCH138 |
Choice of Proton Driver Parameters for a Neutrino Factory
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target, proton, factory, acceleration |
372 |
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- W.-T. Weng, J.S. Berg, R.C. Fernow, J.C. Gallardo, H.G. Kirk, N. Simos
BNL, Upton, Long Island, New York
- S.J. Brooks
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
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A Neutrino Factory typically comprises the following subsystems: proton driver; target; muon collection and conditioning( bunching, phase rotation, and cooling); muon acceleration; and muon decay ring. It takes great effort to design each subsystem properly, such that it can mesh with all other subsystems to optimize the overall facility performance. This optimization is presently being studied as part of the International Scoping Study of a Future Neutrino Factory and Superbeam Facility. This paper will evaluate the implications of other subsystems on the parameters of a proton driver for a Neutrino Factory. At the desired power of 4 MW, the impacts of the choice of the proton energy, bunch length, bunch intensity, and repetition rate on other subsystems are assessed to identify a proper range of operation for each parameter. A suitable "design phase space" of proton driver parameters is defined. Given possible choices of design parameters for proton driver, we compare the performance of a linac, a synchrotron, and an FFAG accelerator. The relative merits of existing proton driver proposals will also be examined.
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TUPCH112 |
Commissioning of the 100 MeV Preinjector HELIOS for the SOLEIL Synchrotron
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emittance, linac, gun, SOLEIL |
1274 |
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- A.S. Setty, D. Jousse, J.-L. Pastre, F. Rodriguez
THALES, Colombes
- R. Chaput, J.-P. Pollina, B. Pottin, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette
- A. Sacharidis
EuroMev, Buc
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HELIOS is the 100 MeV electron linac pre-injector of SOLEIL the new French SR facility. It has been supplied by THALES, as a turn-key system on the basis of SOLEIL APD design. The linac was commissioned in October 2005. This paper will remind the main features of the linac, especially on beam-loading compensation, and will give results obtained during the commissioning tests where a special care has been taken for emittance measurements. Specified and measured beam parameters will be compared to show the performance of the entire system.
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TUPCH117 |
Experience with the 208MHz and 52MHz RF Systems for the HERA Proton Accelerator
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feedback, controls, DESY, injection |
1289 |
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TUPCH128 |
New Cutting Scheme of Magnetic Alloy Cores for J-PARC Synchrotrons
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DIAMOND, synchrotron, acceleration, KEK |
1313 |
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- C. Ohmori, S. Anami, E. Ezura, Y. Funahashi, K. Hara, K. Hasegawa, A. Takagi, M. Toda, K. Ueno, M. Yoshii
KEK, Ibaraki
- Y. Morita, T. Yoshioka
ICEPP, Tokyo
- M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
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A new cutting method using a grindstone was developed to manufacture the magnetic alloy cores. The problem of local temperature rise around the cut surfaces was solved. Long-term high-power tests have been performed for both J-PARC RCS and MR RF systems. Mechanism of local heating, new cutting scheme, and manufacturing method are presented.
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TUPCH130 |
Development of the Feed-forward System for Beam Loading Compensation in the J-PARC RCS
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FIR, FFC, CIC, controls |
1319 |
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- F. Tamura, M. Nomura, A. Schnase, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii
KEK, Ibaraki
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In the J-PARC Rapid Cycling Synchrotron (RCS), the heavy beam loading effects due to the high intensity proton beam must be compensated for stable acceleration. The beam feedforward technique is used to compensate the beam loading in the RCS. We present the development of the feedforward system. We designed and built the full-digital system with modern FPGAs to realize high accuracy, stability and predictability of the compensation. Because of the low Q value of each accelerating cavity, the wake voltage consists of not only the accelerating harmonic component but also higher harmonics. Thus, the system is designed to compensate the beam loading at several harmonics. The system has two parts. In the first part, vector components of the selected harmonic are detected from the beam signal picked up by a wall current monitor. The compensation RF signal is generated from the vector components with proper gain and phase in the latter part. The gain and phase are set individually for each harmonic and each cavity of the twelve cavities. We also present the preliminary test results of the newly developed modules.
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TUPCH186 |
Low Level RF System Development for SOLEIL
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feedback, SOLEIL, simulation, damping |
1447 |
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- P. Marchand, M.D. Diop, F. Ribeiro, R.S. Sreedharan
SOLEIL, Gif-sur-Yvette
- M. Luong, O. Piquet
CEA, Gif-sur-Yvette
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The Low Level RF system that is used in the SOLEIL storage ring consists in fully analog "slow" amplitude, phase and frequency loops, complemented with a direct RF feedback. A fast digital FPGA-based I/Q feedback, currently under development, will be implemented later on. The performance of both systems has been evaluated using a Matlab-Simulink-based simulation tool. The computed and first experimental results are reported.
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TUPCH190 |
Universal Controller for Digital RF Control
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controls, resonance, klystron, feedback |
1459 |
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- S. Simrock
DESY, Hamburg
- W. Cichalewski, M.K. Grecki, G.W. Jablonski
TUL-DMCS, Lodz
- W.J. Jalmuzna
Warsaw University of Technology, Institute of Electronic Systems, Warsaw
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Digital RF control systems allow to change the type of controller by programming of the algorithms executed in FPGAs and/or DSPs. It is even possible to design a universal controller where the controller mode is selected by change of parameters. The concept of a universal controller includes the self-excited-loop (SEL) and generator driven resonator (GDR) concept, the choice of I/Q and amplitude or phase control, and allows for different filters (including Kalman filter and method of optimal controller synthesis) to be applied. Even time-varying mixtures of these modes are possible. Presented is the implementation of such a controller and the operational results with a superconducting cavity.
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THPCH066 |
Transient Beam Loading in the DIAMOND Storage Ring
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DIAMOND, simulation, storage-ring, damping |
2937 |
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- S. De Santis, J.M. Byrd
LBNL, Berkeley, California
- R. Bartolini
Diamond, Oxfordshire
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Harmonic cavity systems have been installed on several 3rd generation light sources to lengthen the bunches and increase the Touschek lifetime. Apart from this beneficial effect, harmonic cavities are known to increase the transient beam loading in high-current machines, due to the presence of gaps in the fill pattern. The amplitude of this effect, which is substantially larger than that caused by the main RF system, can in turn produce considerable variations in bunch length and phase along the train, which result in a significant reduction of the lifetime increase. We have developed a tracking simulation, which we have applied to the analysis of the beam loading transients in Diamond, for the case of passive superconducting harmonic cavities. The influence of beam current, gap amplitude and harmonic cavity tuning on the final lifetime have been studied, as well as the effects of higher-order modes.
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THPLS111 |
Beam Loading Measurement and its Application to the Harmonic RF Control of the APS PAR
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synchrotron, injection, controls, photon |
3538 |
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- C. Yao, E.E. Cherbak, N.P. Di Monte, A. Grelick, T. Smith, B.X. Yang
ANL, Argonne, Illinois
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The particle accumulator ring (PAR) has dual rf systems: a CW mode fundamental rf system (RF1) operating at 9.77 MHz that accumulates multiple linac pulses into a 0.8-ns bunch, and a 12th harmonic rf (RF12) that compresses the bunch length further to 0.34 ns for injection into the booster. The RF12 capture process is critical for optimal performance of the PAR. We investigated the effects of beam loading during the RF12 capture and bunch length compression process with both spectrum analysis and streak camera imaging. Based on these observations, a new timing scheme for the RF12 tuner and power control was implemented, which has substantially improved the performance of the PAR. We report our observation, the new timing scheme, and beam parameters after optimization.
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THPLS112 |
Electron Multipacting Observation and Simulation in the APS PAR
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electron, simulation, vacuum, resonance |
3541 |
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