Paper |
Title |
Page |
MOPC013 |
Design, Fabrication and High Power RF Test of a C-band Accelerating Structure for Feasibility Study of the SPARC Photo-injector Energy Upgrade |
89 |
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- D. Alesini, R. Boni, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo, F. Marcellini
INFN/LNF, Frascati (Roma), Italy
- G. Campogiani, A. Mostacci, L. Palumbo, S. Persichelli, V. Spizzo
Rome University La Sapienza, Roma, Italy
- T. Higo, K. Kakihara, S. Matsumoto
KEK, Ibaraki, Japan
- S. Verdú-Andrés
TERA, Novara, Italy
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The energy upgrade of the SPARC photo-injector from 170 to 250 MeV will be done by replacing a low gradient 3m S-Band structure with two 1.5m high gradient C-band structures. The structures are traveling wave, constant impedance sections, have symmetric waveguide input couplers and have been optimized to work with a SLED RF input pulse. A prototype with a reduced number of cells has been fabricated and tested at high power in KEK (Japan) giving very good performances in terms of breakdown rates at high accelerating gradient (>50 MV/m). The paper illustrates the design criteria of the structures, the fabrication procedure and the high power RF test results.
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MOPS068 |
Localization of Transverse Impedance Sources in the SPS using HEADTAIL Macroparticle Simulations |
757 |
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- N. Biancacci, G. Arduini, E. Métral, D. Quatraro, G. Rumolo, B. Salvant, R. Tomás
CERN, Geneva, Switzerland
- N. Biancacci, M. Migliorati, L. Palumbo
Rome University La Sapienza, Roma, Italy
- R. Calaga
BNL, Upton, Long Island, New York, USA
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In particle accelerators, beam coupling impedance is one of the main contributors to instability phenomena that lead to particle losses and beam quality deterioration. For this reason these machines are continuously monitored and the global and local amount of impedance needs to be evaluated. In this work we present our studies on the local transverse impedance detection algorithm. The main assumptions behind the algorithm are described in order to understand limits in reconstructing the impedance location. The phase advance response matrix is analyzed in particular for the SPS lattice, studying the different response from 90,180,270 degrees phase advance sections. The thin lenses scheme is also implemented and new analytical formulas for phase advance beating were derived. This avails us to put reconstructing lenses everywhere in the lattice, and to study their positioning scheme. Limits in linear response are analyzed. This sets the upper and lower limits in reconstruction to the phase advance measurement accuracy and the linear response regime limit.
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MOPS073 |
Impedance Calculation for Simple Models of Kickers in the Non-ultrarelativistic Regime |
772 |
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- N. Biancacci, N. Mounet, E. Métral, B. Salvant, C. Zannini
CERN, Geneva, Switzerland
- N. Biancacci, M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
- Q. Qin, N. Wang
IHEP Beijing, Beijing, People's Republic of China
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Kicker magnets are usually significant contributors to the beam coupling impedance of particle accelerators. An accurate understanding of their impedance is required in order to correctly assess the machine intensity limitations. The field matching method derived by H. Tsutsui for the longitudinal and transverse dipolar (driving) impedance of simple models of kickers in the ultrarelativistic regime was already extended to the non-ultrarelativistic case, and to the quadrupolar (detuning) impedance in the ultrarelativistic case. This contribution presents the extension to the quadrupolar impedance in the non-ultrarelativistic case, as well as benchmarks with other available methods to compute the impedance. In particular, all the components of the impedances are benchmarked with Tsutsui's model, i.e. in the ultrarelativistic limit, with the model for a flat chamber impedance recently computed by N. Mounet and E. Métral, in the case of finite relativistic gamma, and with CST Particle Studio simulations.
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WEPC107 |
Development of a Steady State Simulation Code for Klystron Amplifiers |
2265 |
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- C. Marrelli
CERN, Geneva, Switzerland
- M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
- B. Spataro
INFN/LNF, Frascati (Roma), Italy
- S.G. Tantawi
SLAC, Menlo Park, California, USA
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The design of klystrons is based on the intensive utilization of simulation codes, which can evaluate the complete beam-cavities interaction in the case of large signals. In the present work, we present the development of a 2-D steady state simulation code that can self-consistently evaluate the effects of the electromagnetic field on the particles and of the particles back on the field. The algorithm is based on the iterative solution of the power balance equation in the RF structures and allows determining the amplitude and phase of the electromagnetic field starting from the cavity modes. Some applications of the code to a single cavity and a two cavity klystron are presented and compared with the results obtained from other codes. The effect of the space charge forces in the klystron drift tubes is also evaluated.
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TUPO008 |
Electron Linac Optimization for Driving Bright Gamma-ray Sources based on Compton Back-scattering |
1461 |
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- L. Serafini, F. Broggi, C. De Martinis, D. Giove
Istituto Nazionale di Fisica Nucleare, Milano, Italy
- D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, E. Chiadroni, G. Di Pirro, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, P. Tomassini, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
- A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
- C. Maroli, V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
- M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
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We study the optimal lay-out and RF frequency for a room temperature GeV-class Electron Linac aiming at producing electron beams that enhance gamma-ray sources based on Compton back-scattering. These emerging novel sources, generating tunable, mono-chromatic, bright photon beams in the range of 5-20 MeV for nuclear physics as well as nuclear engineering, rely on both, high quality electron beams and J-class high repetition-rate synchronized laser systems in order to achieve the maximum spectral density of the gamma-ray beam (# photons/sec/eV). The best option among the conventionally used RF linac-bands (S, C, X) and possible hybrid schemes will be analyzed and discussed, focusing the study in terms of best performances for the gamma-ray source, its reliability and compactness. We show that the best possible candidates for a Gamma-ray driver are quite similar to those of FEL Linacs.
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THYB01 |
Advanced Beam Manipulation Techniques at SPARC |
2877 |
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- A. Mostacci, D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, M. Castellano, E. Chiadroni, G. Di Pirro, A. Drago, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
- A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
- B. Marchetti
INFN-Roma II, Roma, Italy
- M. Migliorati
University of Rome "La Sapienza", Rome, Italy
- L. Palumbo
Rome University La Sapienza, Roma, Italy
- V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
- C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy
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SPARC in Frascati is a high brightness photo-injector used to drive Free Electron Laser experiments and explore advanced beam manipulation techniques. The R&D effort made for the optimization of the beam parameters will be presented here, together with the major experimental results achieved. In particular, we will focus on the generation of sub-picosecond, high brightness electron bunch trains via velocity bunching technique (the so called comb beam). Such bunch trains can be used to drive tunable and narrow band THz sources, FELs and plasma wake field accelerators.
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Slides THYB01 [20.772 MB]
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THPS101 |
Present and Perspectives of the Sparc THz Source |
3669 |
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- E. Chiadroni, M. Bellaveglia, M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, G. Gatti, E. Pace, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
- P. Calvani, S. Lupi, A. Nucara
Università di Roma I La Sapienza, Roma, Italy
- L. Catani, B. Marchetti
INFN-Roma II, Roma, Italy
- A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
- O. Limaj
University of Rome La Sapienza, Rome, Italy
- A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
- C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy
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The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). Its measured peak power is of the order of 108 W, very competitive with respect to other present sources. The present status of the source is presented and future perspectives are presented.
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