isbn 92-9083-231-2 (web version)cufaro/scientific/2004_epac.pdfabreu, natalia lnls [email protected]...

19
ISBN 92-9083-231-2 (Web version) ISBN 92-9083-232-0 (CD-ROM version) Copyright © 2004 by EPAC. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the written permission of EPAC, except as stated below. Single photocopies of single articles may be made for private study or research. Illustrations and short extracts from the text of individual contributions may be copied provided that the source is acknowledged and the permission of EPAC is obtained. Published by the European Physical Society Accelerators Group (EPS-AG) and CERN.

Upload: others

Post on 01-Sep-2020

2 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

ISBN 92-9083-231-2 (Web version) ISBN 92-9083-232-0 (CD-ROM version)

Copyright © 2004 by EPAC. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the written permission of EPAC, except as stated below. Single photocopies of single articles may be made for private study or research. Illustrations and short extracts from the text of individual contributions may be copied provided that the source is acknowledged and the permission of EPAC is obtained. Published by the European Physical Society Accelerators Group (EPS-AG) and CERN.

Page 2: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

CONFERENCE ORGANIZATION

Organized byPaul Scherrer Institut (PSI), Villigen

Under the Auspices ofEuropean Physical Society

Supported by

BESSY INFNCCLRC (ISIS & ASTeC) MSL

CEA DSM NovartisCERN PSIDESY Roche

ELETTRA Synchrotron SoleilESRF Serono

FZ Jülich Swiss International Air LinesFZ Karlsruhe Syngenta

GSI

Chairman Organizing Committee Leonid�Rivkin, PSIChairman Scientific Programme Committee Christopher Prior, ASTeC CCLRC RAL & Trinity College OxfordChairman Local Organizing Committee Hans-Arno Synal, ETH & PSIEPAC Conference Coordinator Christine Petit-Jean-Genaz, CERN

ORGANIZING COMMITTEEC.�Biscari, INFN-LNF, K. Blasche*, GSI, C.�Bocchetta*, Sincrotrone Trieste, J. Bordas, LSB-IFAE, R.�Brinkmann*,DESY, H.�Danared*, MSL, J.-P.�Delahaye*, CERN, J.-M.�Lagniel*, CEA, E.�Lee*, LBNL, A.�Mosnier*, CEA,S.P.�Møller*, ISA, W.�Namkung, PAL, C.�Pagani*, LASA-INFN, Ch. Petit-Jean-Genaz*, CERN, C. Prior*, ASTeCCCLRC RAL & Trinity College Oxford, F.�Ruggiero*, CERN, Y.�Shatunov, BINP, R.�Siemann, SLAC, S.�Smith*,ASTeC CLRC DL, H.-A.�Synal*, ETH & PSI, U.�Van�Rienen, U. Rostock, T. Weiland, TU-Darmstadt, A.�Wrulich,EPFL & PSI* Member of the Scientific Programme Committee

LOCAL ORGANIZING COMMITTEEA.�Adelmann, PSI, M.�Bugmann, PSI, J.�Chrin, PSI, P.�Dietrich, PSI, M.�Heiniger, PSI, C.�Petit-Jean-Genaz, CERN,J.�Poole,�CERN L.�Rivkin, PSI, G.�Schneider, Conventus, D.�Vermeulen, PSI, A.�Wrulich, EPFL and PSI

SCIENTIFIC ADVISORY BOARDN. Angert, GSI, R.�Assmann, CERN, J.�Bergoz, Bergoz Inst., F.�Bordry, CERN, P.�Burrows, QMUL, J.�Byrd, LBNL,Y.�Cho, ANL, L.�Dallin, CLS, D.�Dinev, INRNE, R.�Eichler, PSI, P.�Elleaume, ESRF, M.�Eriksson, MAX-lab,J.X.�Fang, IHIP, Beijing, G.�Fortuna, INFN-LNL, J.�Hangst, IPA, Aarhus, H.�Henke, TU- Berlin, N.�Holtkamp, ORNL,A.�Jackson, ALS, T.�Katayama, INS, Tokyo, D.�Krämer, BESSY, S.�Kulinski, Soltan Inst., S.Y.�Lee, IUCF, M.-P.�Level, Soleil, T.�Linnecar, CERN, G. Luijckx, NIKHEF-K, P.�Maccioni, CERCA, R.�Maier, FZJ, I.�Meshkov, JINR,Y.�Mori, KEK, S.�Nath, LANL, P.�O’Shea, U. Maryland, S.�Ozaki, BNL, R. Penco, Ansaldo, F. Perez, FZK-ISS,L.�Picardi, ENEA, N. Pichoff, CEA, M.�Poole, ASTeC CLRC DL, P.�Raimondi, INFN-LNF, U. Ratzinger, IAP,T.�Raubenheimer, SLAC, D.�Reistad, TSL, G.�Ryckewaert, U. Louvain, P.�Schmüser, DESY, B.�Sharkov, ITEP,Moscow, H.�Tanaka, JASRI, S.�Tazzari, U. Roma II, M.�Tigner, U. Cornell, A.�Tkatchenko, IPN, N.�Vinokurov, BINP,R.�Walker, Diamond, J. Wei, BNL, T.�Weis, U. Dortmund, F.�Willeke, DESY, Y. Yamazaki, J-PARC, K.�Yokoya,KEK, C.�Zhang, BEPC, F.�Zimmermann, CERN

EDITORIAL BOARDJ.�Chrin, PSI, Ch.�Petit-Jean-Genaz, CERN, J.�Poole, CERN, C.�Prior, ASTeC CCLRC RAL & Trinity College Oxford,H.-A.�Synal, ETH & PSI

Page 3: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

LIST OF PARTICIPANTS

ABO-BAKR, Michael BESSY [email protected], Natalia LNLS [email protected], Dean CCLRC RAL [email protected], Andreas Paul Scherrer Institut [email protected], Chris SLAC [email protected], Ilya DESY [email protected]ÏT ABDERRAHIM, Hamid SCK CEN [email protected], Vladimir JINR [email protected], David INFN-LNF [email protected], Juergen Thales Broadcast & Multimedia AG [email protected], Curtis Altair technologies, inc. [email protected], Oscar LBNL [email protected], Ake MAX-Lab, Lund University [email protected], Guillermo MSL [email protected], Deepa CCLRC DL [email protected], Norbert GSI [email protected], Lars DANFYSIK A/S [email protected], Gianluigi CERN [email protected], Tug FNAL [email protected], Luca CERN [email protected], Kurt CERN [email protected], Ralph CERN [email protected], Maher SESAME [email protected], Lucrezia INFN - Gruppo Colleg. di Messina [email protected], Vadim BINP [email protected], Patrick CNRS/IN2P3 [email protected], Robert CERN [email protected], Vincent CERN [email protected], Mei BNL [email protected], Klaus DESY [email protected], Nicolae Hyperion University [email protected], Karl SLAC [email protected], Eric GANIL [email protected], Winfried GSI [email protected], Riccardo Diamond Light Source [email protected], Maria Sonia CERN [email protected], Horst Micro-Epsilon Messtechnik GmbH [email protected], Günter Forschungszentrum Jülich [email protected], Pierre FNAL [email protected], Pierre-Yves CEA [email protected], Reinard Universität Frankfurt [email protected], Peter GSI [email protected], Giulia CCLRC RAL [email protected], Giovani INFN-LASA [email protected], Elena CERN [email protected], Michael CERN [email protected], Giel FOM Institute 'Rijnhuizen' [email protected], J. Scott BNL [email protected], Russ CLS [email protected], Julien Bergoz Instrumentation [email protected], Pierre-Emmanuel CEA [email protected], Axel Institut für Synchronstrahlung [email protected], Stéphane CEA [email protected], Alessandro CERN [email protected], Caterina CERN [email protected], Patrick CEA [email protected]

Page 4: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

BETHUYS, Stephane Thales Electron [email protected]

BHAT, Chandra FNAL [email protected], Ronak MIT [email protected], Ingrid Forschungszentrum Karlsruhe [email protected], Caterina INFN-LNF [email protected], Teruhiko JASRI [email protected], Roger KIPAC [email protected], Klaus GSI [email protected], Willem ORNL [email protected], Hans Advanced Energy Systems, Inc. [email protected], Carlo J Sincrotrone Trieste [email protected], Alexander Forschungszentrum Jülich [email protected], Igor IHEP [email protected]ÖGE, Michael Paul Scherrer Institut [email protected], Inessa Magnetic Sensor Laboratory [email protected], Alexander BINP [email protected], Pierre CEA [email protected], Angelo INFN-LASA [email protected], Sébastien IPN [email protected], Davide CERN [email protected], Hans-Heinrich CERN [email protected], Enrico CERN [email protected], Werner DESY [email protected], J Michael BNL [email protected], Frank DESY [email protected], Reinhard DESY [email protected], Debbie APS [email protected], Daniel FNAL [email protected], Stephen CCLRC RAL [email protected], Kevin BNL [email protected], Pascale Synchrotron SOLEIL [email protected], Christelle LURE [email protected], Warner WBFB [email protected], Stephen CCLRC DL [email protected], Andree Forschungszentrum Rossendorf [email protected], Daniele Sincrotrone Trieste [email protected], Philip QMUL [email protected], Yuri TRIUMF [email protected], Yunhai SLAC [email protected], Rama BNL [email protected], Sergio CERN [email protected], Josep CELLS [email protected], Ofelia CERN [email protected], Roger SLAC [email protected], George SLAC [email protected], Fritz CERN [email protected] LASHERAS, Nuria CERN [email protected], Marco INFN-LNL [email protected], Rainer GANIL [email protected], Edwin LANL [email protected], Cheng-Hsiang NSRRC [email protected], Yu-Chiu Jefferson Lab [email protected], Vincent CERN [email protected], Graham CCLRC DL [email protected], Swapan Jefferson Lab [email protected], Frederic GANIL [email protected], Stephane CEA [email protected], Samy CERN [email protected]

Page 5: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

CHEN, Chiping MIT Plasma Sc. & Fusion Center [email protected], Sifu CAEP [email protected], Vinod CERN [email protected], Oleg Synchrotron SOLEIL [email protected], Alessandro INFN-RM2/U. Rome "Tor Vergata" [email protected], Gianluigi Jefferson Lab [email protected], Jim CCLRC DL [email protected], Michael CCLRC RAL [email protected], Tarcisio Dip. Interateneo di Fisica - Bari [email protected], James Varian Medical Systems [email protected], Mirco CERN [email protected], Jl iThemba LABS [email protected], John GANIL [email protected], Roberto CERN [email protected], Sarah ORNL [email protected] PETRONI, Nicola INFN Bari & Dept of Mathematics [email protected], Les CLS [email protected], Edward Jefferson Lab [email protected], Heiko CERN [email protected], Håkan MSL [email protected], Viatcheslav ORNL [email protected], Daniele Uniiversità del Sannio [email protected] JONG, Mark CLS [email protected] MARIA, Riccardo CERN [email protected] SANTIS, Stefano LBNL [email protected] SIENA, Silvio Università di Salerno [email protected], Franz-Josef SLAC [email protected], Micha Paul Scherrer Institut [email protected], Bernd CERN [email protected], Jean-Pierre CERN [email protected], Theo University of Sannio [email protected], Michel CEA [email protected], Guillaume CEA [email protected], Hideki SPring-8 [email protected] GIACOMO, Marco CEA [email protected], Steven BNL [email protected], Juergen Forschungszentrum Jülich [email protected], Oleksiy GSI [email protected], George University of Oxford [email protected], Anatoliy NSC KIPT [email protected], David SLAC [email protected], Alessandro INFN-LNF [email protected], Angelika BNL [email protected], Martin IAP [email protected], Alexandr FNAL [email protected], Paul CCLRC RAL [email protected], Romuald CEA [email protected], Subhajit CAT [email protected], Maurice GANIL [email protected], Jishnu CAT [email protected], Michael CCLRC DL [email protected], Ralph Paul Scherrer Institut [email protected], Hartmut GSI [email protected], Dieter CELLS [email protected], Carl LANL [email protected], Pascal ESRF [email protected], Malcolm Imperial College London [email protected], Henriette DANFYSIK A/S [email protected], Paul SLAC [email protected]

Page 6: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

ENDO, Kuninori KEK [email protected], Juan INFN-LNL [email protected], Pavel Forschungszentrum Rossendorf [email protected], Alberto INFN-LNL [email protected], Dan CCLRC RAL [email protected], Tai-Ching NSRRC [email protected], Zhigao KEK [email protected], Ruy LNLS [email protected], Stephane CERN [email protected], Angeles IFIC-Univ. of Valencia [email protected], Anthony Advanced Energy Systems, Inc. [email protected], Max CERCA [email protected], Mikhail LSU CAMD [email protected], Robin CEA [email protected], Luis CERN-EPFL [email protected], Massimo INFN-LNF [email protected], Jean-Marc Synchrotron SOLEIL [email protected], Roberto CERN [email protected], David CCLRC RAL [email protected], Wolfram BNL [email protected], Alan SLAC [email protected], Klaus DESY [email protected], Peter GSI [email protected], Doris CERN [email protected], John SLAC [email protected], Giuliano GSI [email protected], Andrea GSI [email protected], Jose LNLS [email protected], Arne Jefferson Lab [email protected], Søren Weber DANFYSIK A/S [email protected], Kazuhiro Muroran Institute of Technology [email protected], Takuji NIRS [email protected], Valeria INFN-LNF [email protected], John ORNL [email protected], Andrew CCLRC DL [email protected], Alessandro INFN-LNF [email protected], Bjorn The Svedberg Labortory [email protected], Romain Paul Scherrer Institut [email protected], Jie LAL [email protected], Michael Babcock Noell Nuclear [email protected], Andreas ACCEL Instruments GmbH [email protected], Ulrich DESY [email protected], Mattias DANFYSIK A/S [email protected], Andrea INFN-LNF [email protected], Paul ORNL [email protected], Stephen SLAC [email protected], George G. H. Gillespie Associates, Inc. [email protected], J. Douglas LANL [email protected], Massimo CERN [email protected], Dario INFN-LASA [email protected], Erion TU Darmstadt [email protected], Brennan CERN [email protected], Vladimir RRC Kurchatov Institute [email protected], Philippe U. Lancaster / CCLRC DL [email protected], Christopher Paul Scherrer Institut [email protected], Valeria CERN [email protected], Silvia CERN [email protected], James CCLRC RAL [email protected], Marc DELTA [email protected]

Page 7: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

GRIESER, Manfred MPI für Kernphysik [email protected], Stephen CCLRC DL [email protected], Bagrat CANDLE [email protected], Oliver DESY [email protected], Konstantin BINP [email protected], Thomas ESRF [email protected], Susanna INFN-LNF [email protected], Ivan NSC KIPT [email protected], Anda Inst. of Lasers, Plasma and Rad. [email protected], Serge BINP [email protected], Frank U. Mainz, Inst. f. Kernphysik [email protected], Timo CERN [email protected], Abdallah CEA [email protected], Robert TU Darmstadt [email protected], Jang Hui DESY [email protected], Sang-Hyo KAERI [email protected], Samy Siemens USA, Inc. [email protected], Robert LANL [email protected], Fred LLNL [email protected], Rainer W GSI [email protected], Claude CERN [email protected], Thomas BNL [email protected], Dirk Universität Rostock [email protected], Robert DELTA [email protected], Richard Cornell University [email protected], Stuart ORNL [email protected], Linda SLAC [email protected], Jimi TU Eindhoven [email protected], Walter GSI [email protected], Steve DESY [email protected], Michael American Science and Engineering [email protected], Mark MIT [email protected], Nathan Qi3 [email protected], Yasunobu KEK [email protected], Rainer Forschungszentrum Jülich [email protected], Georg Cornell University [email protected], Wolfgang CERN [email protected], Albert CERN [email protected], Ingo GSI [email protected], Mariet KVI [email protected], Karsten BESSY [email protected], Jeffrey ORNL [email protected], Stephen FNAL [email protected], Norbert ORNL [email protected], Katja DESY [email protected], Markus FNAL [email protected]ÜLSMANN, Dr. Peter GSI [email protected], Erhard Forschungszentrum Karlsruhe [email protected], Andrew Jefferson Lab [email protected], Takao KEK [email protected], Masahiro ICR, Kyoto University [email protected], Gerhard Paul Scherrer Institut [email protected], Kiichiro SLLS [email protected], Yoshiro KEK [email protected], Masaaki KEK [email protected], Andrey BINP [email protected], Vadim NSC KIPT [email protected], Yoshihisa ICR, Kyoto University [email protected], Yoshiyuki NIRS [email protected]

Page 8: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

JABLONKA, Marcel CEA [email protected], Alan ASP [email protected], Eberhard BESSY [email protected], Stephen CCLRC RAL [email protected], Dietmar Forschungszentrum Rossendorf [email protected], Andreas FNAL [email protected], Jens-Peter DESY [email protected], Dong-O ORNL [email protected], Kenneth LANL [email protected], Jean-Marc CEA [email protected], James CCLRC DL [email protected], Edward IOP Publishing [email protected], Andreas SLAC [email protected], Verena CERN [email protected], Eiji KEK [email protected], Babak Paul Scherrer Institut [email protected], Davit CANDLE [email protected], Alexandre CCLRC DL [email protected], Dobrin TRIUMF [email protected], Thorsten BESSY [email protected], Heung-Sik PAL,POSTECH [email protected], Emanuel Sincrotrone Trieste [email protected], Pavel Tokyo Metropolitan University [email protected], Daniil ITEP [email protected], Klaus GSI [email protected], Ortwin DESY [email protected], Tadamichi KEK [email protected], Reza Jefferson Lab [email protected], Boris Paul Scherrer Institut [email protected], Eberhard CERN [email protected], Joachim DESY [email protected], Roderich LBNL [email protected], Allison Diversified Technologies, Inc. [email protected], Vince Diamond Light Source [email protected], Oliver LMU München [email protected], Jorg BNL [email protected], Shaukat BESSY [email protected], Do Tae PAL POSTECH [email protected], Dong-Eon PAL POSTECH [email protected], Eun-San PAL POSTECH [email protected], Jincheol B PAL POSTECH [email protected], Suk Hong ANL [email protected], Andrew CCLRC RAL [email protected], Junichi KEK [email protected], Hideo RIKEN/SPring-8 [email protected], Charles IAP [email protected], Hans-Udo ACCEL Instruments GmbH [email protected], Horst IAP [email protected], Roman PTB [email protected], Wolf-Dieter ESRF [email protected], Juan CERN [email protected], Jens BESSY [email protected], Toshiaki SPring-8/JASRI [email protected], Andriy JINR [email protected], Claude Alstom Magnets, Superconductors [email protected], Sergei ITEP [email protected], Vladimir BINP [email protected], Timo Paul Scherrer Institut [email protected], Alexander CERN [email protected]

Page 9: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

KOSCIELNIAK, Shane TRIUMF [email protected], Barbara Forschungszentrum Karlsruhe [email protected], Alexandre JINR [email protected]ÄMER, Dieter BESSY [email protected], Mikhail DESY [email protected], Juraj Paul Scherrer Institut [email protected], Detlef ACCEL Instruments GmbH [email protected], Kristina SLAC [email protected], Kai-Uwe IAP [email protected], Marco TU Darmstadt [email protected], Changhor NSRRC [email protected], Ryunosuke Waseda University [email protected], Shin-ichi KEK [email protected], Volodymyr NSC KIPT [email protected], Peter BESSY [email protected], Vasily BINP [email protected], Slawomir LBNL [email protected] CHINA, Marco CERN [email protected], Jean-Michel CEA [email protected], Guillaume CEA [email protected], Thierry CNRS-IN2P3 [email protected], Luisella CERN [email protected], Thomas TU Darmstadt [email protected], Michael TRIUMF [email protected], Wesley University of Maryland [email protected], Valeri FNAL [email protected], Greg ASP [email protected], Paul L. G FNAL [email protected], Philippe CERN [email protected], Eunhee PAL POSTECH [email protected], Seishu KEK [email protected], Tae Yeon PAL,POSTECH [email protected], Jerry FNAL [email protected], Jean IPN [email protected], Eliane ANL [email protected], Greg SLAC [email protected], Ming CAEP [email protected], Yanxia CPI Inc. [email protected], Yongjun DESY [email protected], Zenghai SLAC [email protected], Joseph Columbia University [email protected], Lutz DESY [email protected], Mats CERN [email protected] SMITH, Christopher UKAEA [email protected], Augusto INFN-LNL [email protected], Mauricio LAL - IFUSP [email protected], Derek BNL [email protected]ÜDEKE, Andreas Paul Scherrer Institut [email protected], Jom TU Eindhoven [email protected], Dmitry GSI [email protected], John LANL [email protected], Remo CERN [email protected], Allan University of Abertay [email protected], Edgar CERN [email protected], Hubert Schulz-Electronic GmbH [email protected], Django CERN [email protected], Paolo Saes Getters Spa [email protected], Elena CERN [email protected], Fabio INFN-LNF [email protected]

Page 10: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

MARCHAND, Patrick Synchrotron SOLEIL [email protected], Israel Soreq NRC [email protected], Frank BESSY [email protected], Neil CCLRC DL [email protected], Sebastien CERN [email protected], Zeus CELLS [email protected], Ian Diamond Light Source [email protected], Siegfried Forschungszentrum Jülich [email protected], Maria Rosaria INFN [email protected], Brandin MAX-Lab, Lund University [email protected], Marco INFN-LASA [email protected], William BNL [email protected], Malika CERN [email protected], Robert YerPhI [email protected], Lia Jefferson Lab [email protected], Volker CERN [email protected], Wolfhard DESY [email protected], Atoosa BESSY [email protected], Igor JINR [email protected], Oleg BINP [email protected], Pierre TPC [email protected], Vladimir JINR [email protected], Catia INFN-LNF [email protected], Michiko DESY [email protected], Andrey American Science and Engineering [email protected], Toshiyuki KEK [email protected], Sadao Mitsubichi Heavy Industries, Ltd. [email protected], Alexendre KEK [email protected], Wim CEC-JRC-IRMM [email protected], Christoph BNL [email protected], Alun Diamond Light Source [email protected], Gebhard GSI [email protected], William CCLRC RAL [email protected], Herbert O Singapore SLS [email protected], Alban CEA [email protected], Mike TRIUMF [email protected], Anke-Susanne Forschungszentrum Karlsruhe [email protected], Norbert IAP [email protected], Wolfgang TU Darmstadt [email protected]ÑOZ, Marc CELLS [email protected], Bruno CCLRC RAL [email protected], Graeme ORNL [email protected], James BNL [email protected], Edil GSI [email protected], Toshiya KEK [email protected], Stephen CERN [email protected], Andriy NSC KIPT [email protected], Amor Synchrotron SOLEIL [email protected], Sergei FNAL [email protected], Ryutaro Synchrotron SOLEIL [email protected], Norio ISSP, University of Tokyo [email protected], Takeshi JASRI [email protected], Masahiko Hitachi Ltd.NAM, Sang Hoon PAL, POSTECH [email protected], Stephan TU Darmstadt [email protected], Monica Inst. Lasers, Plasma and Rad. Phys. [email protected], Inna GSI [email protected], Axel BESSY [email protected], Oleg Omega-P, Inc. [email protected]

Page 11: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

NGUYEN, Quyet Huu Univ. Tokyo [email protected], Bertrand CERN [email protected], Bjarne Roger DANFYSIK A/S [email protected], Jørgen S ISA, University of Aarhus [email protected], Sergei BINP [email protected], Shigeshi KEK [email protected], David CERN [email protected], Akira ICR, Kyoto University [email protected], Koji NIRS [email protected], Jim ANL [email protected], Peter CCLRC RAL [email protected], Tomohiro JAERI [email protected], Chihiro KEK [email protected], Takashi JASRI/SPring-8 [email protected], Norihito KEK [email protected], Guillaume CNRS/IN2P3 [email protected], David ORNL [email protected], Nikolay NSC KIPT [email protected], Jean-Michel CNRS [email protected], Peter ANL [email protected], Vladimir Leybold Vakuum Dresden GmbH [email protected], Hywel CCLRC DL [email protected], Satoshi BNL [email protected], Andreas MSL [email protected], Carlo INFN & DESY [email protected], Chien-Ih BNL [email protected], Antonio INFN-LNL [email protected], Luigi U. Roma La Sapienza & INFN-LNF [email protected], Jian CAEP [email protected], Ioannis ESRF [email protected] MØLLER, Søren ISA, University of Aarhus [email protected], Martin Paul Scherrer Institut [email protected], In Soo PAL,POSTECH [email protected], Ki-Hyeon PAL,POSTECH [email protected], Ramon ALBA Synchotron [email protected], Matteo Sektion Physik LMU [email protected], Jacques CEA [email protected], Ken CCLRC RAL [email protected], Marco Paul Scherrer Institut [email protected], Stephen BNL [email protected], Michael ACCEL Instruments GmbH [email protected], Luigi INFN-LNF [email protected], Francisco CELLS [email protected], Thomas ESRF [email protected], Christine CERN [email protected], Alexey BINP [email protected], Marzik YerPhI [email protected], Thomas CERN [email protected], Nan SLAC [email protected], LUIGI ENEAPICHOFF, Nicolas CEA [email protected], Eugene LETI [email protected], Tatiana University of Milan / CERN [email protected], Mauro SLAC [email protected], Roman JINR [email protected], Eric ESRF [email protected], Fedor BINP [email protected], Holger IAP [email protected], Roger TRIUMF [email protected]

Page 12: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

POLOZOV, Sergey MEPHI [email protected], Montserrat CELLS [email protected], John CERN [email protected], Mike CCLRC DL [email protected]ÖPLAU, Gisela Universität Rostock [email protected], Eugeni A.F. Ioffe Physicotechnical Inst. [email protected], Milorad FNAL [email protected], Anna Maria INFN-LNL [email protected], Christopher CCLRC RAL [email protected], Dieter DESY [email protected], Torsten BESSY [email protected], Marcello ENEA [email protected], Eamonn CCLRC RAL [email protected], Jean-Yves Paul Scherrer Institut [email protected], Pantaleo INFN-LNF [email protected], Délio CERN [email protected], Christian CERN [email protected], Tor SLAC [email protected], Maurizio INFN-LNS [email protected], Stefano CERN [email protected], Guenther Diamond Light Source [email protected], Ina LBNL [email protected], Hartmut GSI [email protected], Dag The Svedberg Laboratory [email protected], Vittorio CERN [email protected], Roland MPI for Nuclear Physics [email protected], Ximenes LNLS [email protected], Vladimir BINP [email protected], Adriaan CERN [email protected], Sakhorn FNRF [email protected], Robert Jefferson Lab [email protected], Leonid Paul Scherrer Institut [email protected], Guillaume CERN [email protected], Jose Alberto NSCL [email protected], Peter CERN [email protected], Concetta ENEA [email protected], Thomas BNL [email protected], Jorg Universitat Hamburg [email protected], Lucio CERN [email protected], Robert Forschungszentrum Karlsruhe [email protected], Markus TU Darmstadt [email protected], Gary LANL [email protected], Raphaël LAL [email protected], Alessandro G BNL [email protected], Francesco CERN [email protected], Giovanni GSI [email protected], Thomas BNL [email protected], Rok Josef Stefan Institute / Cosylab [email protected], James SLAC/SSRL [email protected], Gajendra Kumar DESY [email protected], Kazuyoshi Hitachi Ltd. [email protected], Fumio SHI [email protected], Hiroshi ISSP, University of Tokyo [email protected], Izumi KEK [email protected], Shogo KEK [email protected], Kazuyuki Waseda university [email protected], Fernando LBNL [email protected], Alejandro CERN [email protected], Akira Osaka University [email protected]

Page 13: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

SATOGATA, Todd BNL [email protected], Andreas IAP [email protected], Aleksandr American Science and Engineering [email protected], Masaru JAERI [email protected], Walter CERN [email protected], Paolo Università degli Studi di Milano [email protected], Alwin Univ. Frankfurt [email protected], Thomas Paul Scherrer Institut [email protected], Detlev University of Dortmund [email protected], Volker Paul Scherrer Institut [email protected], Rudiger CERN [email protected], Thomas Paul Scherrer Institut [email protected], Uwe DESY [email protected], Sascha TU Darmstadt [email protected], Siegfried DESY [email protected], David SLAC [email protected], Marcus GSI [email protected], Luigi CERN [email protected], Duncan CCLRC DL [email protected], Richard CERN [email protected], Mike DESY [email protected], Jacek DESY [email protected], Igor JINR [email protected], Yurij Forschungszentrum Jülich [email protected], Luc CERN [email protected], Vincent ESRF [email protected], Daniele INFN-LASA [email protected], Andrew LBNL [email protected] , Andrew Thales Communications [email protected], Elena CERN [email protected], Yuri BINP [email protected], Thomas ORNL [email protected], Ron e2v technologies Ltd. [email protected], Ben CCLRC DL [email protected], Joseph LANL [email protected], Vladimir JINR [email protected], Vladimir FNAL [email protected], Yoshito KEK [email protected], Katsuhiro LNS, Tohoku University [email protected], Toshiyuki ICR, Kyoto University [email protected], Yoshihisa KEK [email protected], Masashi KEK [email protected], Grigori JINR [email protected], Valery BINP [email protected], Yoshihiko LASTI, University of Hyogo [email protected], Alexei JINR [email protected], Ricard Mark CLS [email protected], Karl FSUE "RPC "Istok" [email protected], Ansgar MSL [email protected], Stefan DESY [email protected], Sergey BINP [email protected] , Blazej CERN [email protected], Henrik DANFYSIK A/S [email protected], Victor BINP [email protected], John BNL [email protected], Kevin S BNL [email protected], Robert J CCLRC DL [email protected], Susan CCLRC DL [email protected], Nickolay MEPHI [email protected]

Page 14: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

SORTAIS, Pascal IN2P3 [email protected], Jens CERN [email protected], Peter GSI [email protected], Daryl SLAC [email protected], Giulio U. Ferrara and INFN Legnaro [email protected], Rolf Forschungszentrum Jülich [email protected], Markus GSI [email protected], Bernd DESY [email protected], Christoph LBNL [email protected], Bastian TU Darmstadt [email protected], Ralph CERN [email protected], Erik DANFYSIK A/S [email protected], James ORNL [email protected], Jan CERN [email protected], James FNAL [email protected], Andreas Paul Scherrer Institut [email protected], Guy CERN [email protected], Yusuke KEK [email protected], Hyung Suck PAL,POSTECH [email protected], Victor CAMD [email protected], Shinsuke SPring-8/JASRI [email protected], Toshio KEK [email protected], Michele Sincrotrone Trieste [email protected], Hans-Arno ETH / Paul Scherrer Institut [email protected], Evgeny JINR [email protected], Balazs CERN [email protected], Mauro CERN [email protected], Naeem GSI [email protected], Junpei Tokyo Institute of Technology [email protected], Masaru SPring-8/JASRI [email protected], Shigeru KEK [email protected], Takeshi ICR, Kyoto University [email protected], Vadim IHEP [email protected], Richard Cornell University [email protected], Hitoshi JASRI [email protected], Minoru RRI, Kyoto University [email protected], Sami SLAC [email protected], Hamed MAX-Lab, Lund University [email protected], Pedro LNLS [email protected], Jochen Forschungszentrum Rossendorf [email protected], Peter SLAC [email protected], Dmitry SLAC [email protected], Justin CCLRC DL [email protected], Jan IAP [email protected], Manfred EAS [email protected], Chris CCLRC RAL [email protected], John CCLRC RAL [email protected], Neil CCLRC DL [email protected], Kevin CCLRC RAL [email protected], Leonid IHEP [email protected], André CNRS/IN2P3/IPNO [email protected], Jean-Philippe CERN [email protected], Raimund Forschungszentrum Jülich [email protected], Manfred RWTH Aachen [email protected], Marie-Agnes Synchrotron SOLEIL [email protected], Kota KEK [email protected], Bob CPI Inc. [email protected], Takeshi KEK [email protected]Ò, Antonio INFN- Gruppo Colleg. di Messina [email protected]

Page 15: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

TRINES, Dieter DESY [email protected], Jacky(hung-Jen) NSRRC [email protected], Koji JASRI/SPring-8 [email protected], Joachim CERN [email protected], James SLAC [email protected], Tomonori NIRS [email protected], Klaus Bergoz Instrumentation [email protected], Junji KEK [email protected], Peter CERN [email protected], Rok Instrumentation Technologies [email protected], Vyacheslav NSC KIPT [email protected], Jan CERN [email protected], Cristina INFN-LNF [email protected], Vittorio Giorgio University of Naples [email protected], Anne-Marie Jefferson Lab [email protected] DER GEER, Bas Pulsar Physics [email protected] DER WIEL, Marnix TU-Eindhoven [email protected] RIENEN, Ursula Rostock University [email protected] ZEIJTS, Johannes BNL [email protected], Nikita Forschungszentrum Jülich [email protected], Gueorgui FNAL [email protected] DELSOLARO, Walter CERN [email protected]ÁNDEZ, Antonio CERN [email protected], Carlo INFN-LNF [email protected], Mikael Scanditronix Magnet AB [email protected], Gaetano SESAME [email protected], Vasilis CERN [email protected], Arnold SLAC [email protected], Jos CERN [email protected], Hanspeter ACCEL Instruments GmbH [email protected], Mathias DESY [email protected], Valery JINR [email protected], Vladimir BINP [email protected] STEIN, Peter ACCEL Instruments GmbH [email protected] HAHN, Robert MPI für Kernphysik [email protected], Louis CERN [email protected], Richard Diamond Light Source [email protected], Erik ESRF [email protected], Chun-Xi ANL [email protected], Fuhua MIT [email protected], Jiuqing IHEP [email protected], Ju ANL [email protected], Rainer DESY [email protected], Robert SLAC [email protected], Christopher CCLRC RAL [email protected], Fuqiang Paul Scherrer Institut [email protected], Jie BNL [email protected], Ernst BESSY [email protected], Thomas TU Darmstadt [email protected], Udo GSI [email protected], Hans DESY [email protected], Sylvain CERN [email protected], Carsten MPI für Kernphysik [email protected], Sverker MAX-Lab, Lund University [email protected], Stephen CCLRC RAL [email protected], Christopher CCLRC DL [email protected], Glen Queen Mary, U. of London [email protected], Uli SLAC [email protected], David e2v technologies Ltd. [email protected]

Page 16: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

WILDNER, Elena CERN [email protected], Klaus University of Dortmund [email protected], Axel DESY/RWTH Aachen [email protected], Kay DESY [email protected], Mark SLAC [email protected], Emma CCLRC DL [email protected], Ed CPI Inc. [email protected], Albin F Paul Scherrer Institut / EPFL [email protected], Godehard BESSY [email protected], Kazuo RIKEN [email protected], Yoshio Japan Nuclear Cycle Dev. Inst. [email protected], Jinfeng Osaka University [email protected], Jongchel PAL POSTECH [email protected], Yoichi Osaka University [email protected], Volodymyr NASU/IOC [email protected], Dino Sincrotrone Trieste [email protected], Andrey NSC KIPT [email protected], Markus CERN [email protected], Zhentang SINAP [email protected], Alexander LBNL [email protected], Volker Uppsala University [email protected], Thomas MAN [email protected], Frank CERN [email protected], Holger IAP [email protected], Alexander FNAL [email protected], Mikhail INFN-LNF [email protected], Abbi MIT [email protected], Günter TU Dresden [email protected], Vasily IHEP [email protected], Townsend MIT [email protected], Robert University of Texas at Austion [email protected]

Page 17: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

NON GAUSSIAN TRANSVERSE DISTRIBUTIONSIN A STOCHASTIC MODEL FOR BEAM HALOS

N. Cufaro Petroni, Bari University, INFN Sez. Bari, ItalyS. De Martino, S. De Siena, and F. Illuminati, Salerno University, INFN Sez. Napoli, Italy

Abstract

We face, in a stochastic framework, the problem of thehalo formation in high intensity beams of charged particles.We sum up our recent results on this argument, and in thefinal part of the paper we introduce non Gaussian distribu-tions as good candidates to account for sensible escape ofparticles from the density core.

INTRODUCTION

In high intensity beams of charged particles, proposed inrecent years for a wide variety of accelerator–related appli-cations, it is very important to keep at low level the beamloss to the wall of the beam pipe, since even small frac-tional losses in a high–current machine can cause exceed-ingly high levels of radioactivation. However, numericalsimulations, and a few experiments at high current pro-ton linacs, suggest that an extended, low–density halo isformed around the beam: it is then necessary to obtain amore quantitative understanding of the physics of the halo,in order to control and reduce its undesirable effects. In re-cent papers [1, 2] we faced this problem in the frameworkof a stochastic approach to the collective beam dynam-ics. Charged particle beams are usually described eitherin terms of classical dynamical systems, i. e. by a collision-less plasma with the dynamics of a suitable phase space, orby a Fokker–Planck equation in the phase–space variables.In our alternative approach [3] we propose instead to de-scribe the collective dynamics of the particle beams by astochastic and time–reversal invariant description in con-figuration space. This picture is effective in the regime ofstability, where a balance is realized between the energydissipation and the external energy pumping. The sam-ple paths of the representative particle are described by adiffusive stochastic differential equation ruled by the beamemittance, and the two coupled stochastic–hydrodynamicequation describing the dynamics of the beam density pro-file and the motion of its center are derived by a stochas-tic variational principle [4]. The two coupled equationsare also equivalent to a unique linear equation of the formof a (mesoscopic) Schrodinger equation, with the univer-sal Planck constant replaced by the emittance of the beam.Our approach, starting by an apparently different point ofview, formally converges then to the so–called quantum–like approach to beam dynamics [5]. In the framework ofour scheme is also possible to implement an active con-trol for the beam dynamics [6], an aspect which could beuseful in order to eliminate halos. In references [1, 2] we

have adapted our scheme to a preliminary study of the prob-lem of halo formation and control, and we have describedthe collective, not deterministically controllable effects bydiffusive (Gaussian) fluctuations. In the present paper wemake the hypothesis that non–Gaussian processes, for ex-ample the family of the Student distributions, with longertails and non-zero jump probability could provide a betterunderstanding of the long–distance particle behavior.

STOCHASTIC MODEL FOR HALOS

The coupled stochastic–hydrodynamic equations de-rived by the stochastic variational principle [4] and describ-ing the particle beam dynamics in the stability regime [3]take the form , respectively, of a continuity equation:

∂tρ = −∇ · (ρv) , (1)

and of an evolution (Madelung) equation for the conserva-tive dynamics

∂tS +m

2v2 − 2mD2∇2√ρ√

ρ+ V (r, t) = 0 , (2)

where , if m is the mass of a particle, the drift velocityand the (Jacobi-Madelung) function S are connected by thegradient form mv = ∇S, and the diffusion coefficient isproportional to the beam emittance α: α = 2mD. Eqns.(1) and (2) describe the collective behavior of the beam ateach instant of time through the evolution of both its par-ticle density and its velocity field. Introducing the repre-sentation ψ =

√ρ eiS/α , the two coupled real equations

(1) and (2) are equivalent to a single complex Schrodingerequation for the function ψ, with the Planck action constanth replaced by the unit of action α:

iα∂tψ = − α2

2m∇2ψ + V ψ . (3)

In this “Schrodinger-like” (Sl) formulation the phenomeno-logical “wave function” ψ carries the information on thedynamics of both the beam density and the beam velocityfield, since the velocity field is determined via the gradientrelation by the phase function S.

Space–charge effects

Among the various possible sources of halos, in [1] wehave taken into account the spreading effects due to thepresence of a space–charge distribution in the frameworkof our approach. We have implemented the Sl-equation (3)

Proceedings of EPAC 2004, Lucerne, Switzerland

2056

Page 18: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

1 2 3 4 5

0.2

0.4

0.6

0.8

1

s

s w2�s�

Figure 1: The radial distribution sw2(s) compared withthe distribution in absence of space charge (dashed line)for a strong space-charge strength . All quantities are di-mensionless.

in a cylindrically symmetric configuration and coupled itwith the Maxwell equations for the electromagnetic fieldgenerated by the charge distribution. We have thus ob-tained two nonlinear coupled equations. Considering thestationary distribution of the particle density, we have ob-tained that the density profile associated to the presence ofspace–charge is sensibly spread with respect to the Gaus-sian profile obtained if space–charge is absent (see Fig. 1).The distribution exhibits a larger dispersion, and we haveshown that, for sufficiently intense charge density, we canfind up to 105 particles per meter beyond a distance of 10σ(with σ denoting the width of the Gaussian core), at vari-ance with the zero particles in absence of charge effects.

Stationary halo distributions

The solutions discussed in the previous subsection havebeen obtained through a numerical approach, because thenonlinearly coupled equations do not allow for exact ana-lytical solutions. In the same reference [1] we have thenalso employed a variational technique to obtain an approx-imate analytical version of the numerical solution for thedensity profile. In fact, an analytic expression for the den-sity profile leads to analytical forms for the drift velocityand the generating potential, which in turn are needed ifone wish to engineer a controlling mechanism to eliminatethe halo. We have then optimized a reasonable test formfor the density profile, and we have found that the varia-tional solutions show the presence of a node in the densityprofile, and a corresponding singularity in the potential. Anode can be the signature for the presence of a ring–shapedhalo, well separated by the core; in fact, it is completelyopen the question if halo is due to long tails in the den-sity distribution, or if a true halo must be separated fromthe core. On the other hand, we have obtained a tail byspace–charge effects, which however are not the only pos-sible source of halo. Then, in the spirit of a preliminary in-quiry about both the interpretations, we have reversed ourpoint of view; we have in fact explicitly introduced a re-alistic ring distribution, and we have used the dynamicalequations to obtain information on the characteristics of the

associated potential and of the associated velocity fields.The potential exhibits an extra relative maximum if com-pared with the harmonic one, while in correspondence thevelocity field exhibits a “bump” with respect to the straight(linear) behavior.

Dynamical control of the halo

In reference [2] we have extended our analysis to theproblem of the halo dynamics, considering both the thehalo elimination and its reformation. This last problemcannot be accounted for in a pure Quantum–like (Ql) de-scription since, because of the stochastic extremal princi-ple, a change in the distribution produces a change in thedynamics. On the other hand the Ql dynamics leads todistributions which are stable attractors; thus, the halo, ifscraped away, will be restored in characteristic times, butthrough a not extremal Fokker–Planck evolution. We havethen accordingly modified our scheme: the velocity fieldchanges slowly on the relaxation time scales, while the evo-lutions are ruled only by a Fokker–Planck equation until thebalance has been restored. We got an estimate of the timeτ needed by a non stationary, halo–free distribution to re-lax toward the stationary distribution with a halo when thedynamics is supposed frozen in the configuration that pro-duces this halo: we have obtained τ ≈ 10−8÷10−7sec [2].Since this relaxation time depends on the parameters of ourbeam, a comparison with possibly measured phenomeno-logical times could constitute a good check on the sound-ness of the model. We have also begun to analyze possibletransitions from a beam with halo toward a halo–free one,putting an emphasis on the possible dynamics which allowsthis halo elimination.

NON GAUSSIAN DISTRIBUTIONS

Non gaussian stationary states

Values of the maximum-to-RMS ratio as large as 10 or12 have been observed in simulations and it is generallyagreed that this is called halo (see [8] p. 286). Hence thereare good reasons to try non gaussian transverse distribu-tions with longer tails so that the probability of finding par-ticles far away from the beam axis becomes larger. Gener-alized Student distributions Σ(ν; a2)

f(x) =Γ

(ν+12

)

√π Γ

(ν2

)aν

(a2 + x2)ν+12

, ν > 0. (4)

are good candidates. They have finite variance σ2 only forν > 2 and a2 = (ν − 2)σ2. Moreover Σ(ν, (ν − 2)σ2)converges in distribution to N (0, σ2) for ν → +∞. Theradial control potential for a stationary cylindrical beam:

Vν(r) =α2

2mσ2r2 (ν + 2)

r2

ν−2 + (ν + 10)σ2

4

[r2 + (ν − 2)σ2]2

tends to be harmonic for ν → +∞, and is constant beyonda certain radius. This possibly points to some effect due tothe presence of the conducting walls.

Proceedings of EPAC 2004, Lucerne, Switzerland

2057

Page 19: ISBN 92-9083-231-2 (Web version)cufaro/scientific/2004_EPAC.pdfABREU, Natalia LNLS natalia@lnls.br ADAMS, Dean CCLRC RAL Dean.Adams@rl.ac.uk ADELMANN, Andreas Paul Scherrer Institut

Levy driven processes

The trajectories of a process with a stationary StudentΣ(ν, (ν − 2)σ2) ground state can be simulated from theGaussian driven SDE

dX(t) = vν(X(t))dt +√

2D dW (t)

with suitable velocity field. On the other hand a differ-ent kind of process can be generated by independent incre-ments with Student law (4) through a SDE

dX(t) = β(X(t))dt + γ dS(t)

where dS(t) is distributed according to Σ(ν; a2), and β(x)is a suitable velocity field. No complete theory is availablefor a Levy driven stochastic mechanics.

The Student distributions Σ(ν; a2) are infinitely divisi-ble (Levy distributions) [9]. Hence they are possible limitdistributions of row-sums of r.v.’s, but different from thegaussian. As every infinitely divisible law, the Σ(ν; a2)are possible distributions of the increments of a Markovprocess with independent increments (Levy process) [10].Non-gaussian Levy processes have moving discontinuities:only gaussian Levy processes have almost every trajec-tory everywhere continuous [11]. The standard exampleof a non-gaussian Levy process is the compound Poissonprocess. The rate of occurrence, and the height of themoving discontinuities are regulated by the Levy functionLt(x) characteristic of a given process with independentincrements [11]. However the Levy function of a StudentΣ(ν; a2) process is not explicitly known.

Discontinuities in these processes can be used to de-scribe the occasional escape of particles out from an other-wise well collimated beam in an accelerator. Moreover, bysuitably tuning the parameters (a and ν) we can also keepthe transverse distribution of the beam reasonably close to agaussian. We can contrast the trajectories for both a Gaussand a Student process with comparable dispersions. In theFigures 2, 3 a few examples of the Student trajectories areproduced. Since for fixed a the Student variance (whichdiverges for 0 < ν ≤ 2) is a decreasing function of ν, it isapparent that also the jump probability and their length willgenerally decrease with ν. The Figures for ν > 2 (finite,decreasing variance) are selected among the possible casesby excluding all the trajectories showing an almost gaus-sian behavior. For ν > 2 several trials are needed beforegetting a trajectory definitely drifting away from the beamcore.

In this model we suppose that a Student-Levy noisewill be active only inside the beam, while beyond a givendistance from the core the process will be driven by aGauss noise; moreover the velocity field attracts the trajec-tory back toward the core only in its neighborhood, whilebeyond a given distance the process is just a free diffu-sion. Remark that in this example the Gaussian trajectorieswould be essentially that of an Ornstein–Uhlenbeck pro-cess.

-300

-200

-100

Figure 2: Student process with ν = 2.0

25

50

75

100

125

Figure 3: Student process with ν = 3.0

We conclude by remarking that in our opinion for a halomodel the possibility of rare, long jumps in the trajecto-ries is more relevant than just the modest increase in thevariance produced by the Student noise with respect to theGauss (almost everywhere continuous) noise.

REFERENCES

[1] N. Cufaro Petroni, S. De Martino, S. De Siena, and F. Illu-minati, Phys. Rev. ST Accel. Beams 6, 034206 (2003).

[2] N. Cufaro Petroni, S. De Martino, S. De Siena, and F. Illu-minati, Int. Journal of Mod. Phys. B 18, 607 (2004).

[3] N. Cufaro Petroni, S. De Martino, S. De Siena, and F. Illu-minati, Phys. Rev. E 63, 016501 (2001)

[4] F. Guerra and L. M. Morato, Phys. Rev. D 27, 1774 (1983);E. Nelson, Quantum Fluctuations (Princeton UniversityPress, Princeton N. J., 1985).

[5] R. Fedele, G. Miele and L. Palumbo, Phys. Lett. A 194, 113(1994), and references therein; S. I. Tzenov, Phys. Lett. A232, 260 (1997).

[6] N. Cufaro Petroni, S. De Martino, S. De Siena, and F. Illu-minati, J. Phys. A 32, 7489 (1999).

[7] N. Cufaro Petroni, S. De Martino, and S. De Siena, Phys.Lett. A 245, 1 (1998).

[8] T. Wangler, RF Linear accelerators (Wiley, New York1998).

[9] L. Bondesson, Generalized gamma distributions and relatedclasses of distributions and densities (Springer, New York1992).

[10] W. Feller, An introduction to probability theory and its ap-plications - vol. II 2nd edition (Wiley, New York 1971).

[11] M. Loeve, Probability theory - vol, II 4th edition (Springer,New York 1978).

Proceedings of EPAC 2004, Lucerne, Switzerland

2058