International Committee for Future Accelerators Sponsored by the Particles and Fields Commission of IUPAP Beam Dynamics Newsletter No. 33 Issue Editors: K.Ohmi and M. Furman Editor in Chief: W. Chou April 2004 3 CONTENTS 1 FOREWORD..........................................................................................................9 1.1 FROM THE CHAIRMAN............................................................................................9 1.1.1 Changes in the Panel......................................................................................9 1.1.2 Panel activities in 2004:..................................................................................9 1.1.3 ICFA and the Linear Collider.......................................................................10 1.1.4 Other issues..................................................................................................10 1.2 FROM THE EDITORS..............................................................................................11 1.3 ICFA STATEMENT ON LINEAR COLLIDERS.........................................................11 2 ELECTRON CLOUD EFFECTS IN ACCELERATORS...............................14 2.1 ELECTRON CLOUD BUILD UP IN MACHINES WITH SHORT BUNCHES.................14 2.1.1 Introduction..................................................................................................14 2.1.2 Primary Electrons.........................................................................................14 2.1.3 Beam-Induced Multipacting.........................................................................16 2.1.4 Secondary Emission Yield...........................................................................18 2.1.5 Saturation......................................................................................................20 2.1.6 Cloud Decay and Electron Survival.............................................................20 2.1.7 Remedies......................................................................................................21 2.1.8 References....................................................................................................23 2.2 COUPLED-BUNCH INSTABILITY CAUSED BY ELECTRON CLOUD...........................24 2.2.1 Introduction..................................................................................................24 2.2.2 Characterization of Coupled-Bunch Instability from bunch oscillations.....25 2.2.3 References....................................................................................................29 2.3 SINGLE BUNCH INSTABILITIES INDUCED BY ELECTRON CLOUD IN SHORT POSITRON/PROTON/ION BUNCHES.........................................................................29 2.3.1 Introduction..................................................................................................30 2.3.2 Review of the observations and approaches to the problem........................31 2.3.3 Simulation codes for single bunch instabilities and applications.................33 2.3.4 Peculiarities of the electron cloud wake fields.............................................37 2.3.5 Miscellaneous...............................................................................................38 2.3.6 Acknowledgements......................................................................................42 2.3.7 References....................................................................................................42 2.4 MEASURING THE PROPERTIES OF THE ELECTRON CLOUD AT THE ADVANCED PHOTON SOURCE...................................................................................................43 2.4.1 Experimental results.....................................................................................44 2.4.2 Beam-cloud interaction and EC amplification.............................................45 2.4.3 Simulations...................................................................................................47 2.4.4 Superconducting undulator (SCU)...............................................................48 2.4.5 Summary.......................................................................................................48 4 2.4.6 Acknowledgement........................................................................................51 2.4.7 References.....................................................................................................51 2.5 MEASUREMENT OF ELECTRON CLOUD EFFECTS IN KEKB..................................52 2.5.1 Introduction...................................................................................................52 2.5.2 Measurement of electron cloud.....................................................................53 2.5.3 Beam size blow-up.......................................................................................54 2.5.4 Transverse coupled bunch instability...........................................................54 2.5.5 Effect of solenoid..........................................................................................54 2.5.6 Effect of wiggler magnets.............................................................................55 2.5.7 Summary.......................................................................................................55 2.5.8 References.....................................................................................................56 2.6 MEASUREMENT OF ION EFFECTS IN KEKB..........................................................58 2.6.1 Introduction...................................................................................................58 2.6.2 Experiment of the fast ion instability [1]......................................................58 2.6.3 Measurement of transverse coupled bunch instability [5]............................59 2.6.4 References.....................................................................................................60 2.7 STUDIES ON ELECTRON CLOUD INSTABILITY IN THE BEPC...............................60 2.7.1 Introduction...................................................................................................61 2.7.2 Experimental studies.....................................................................................61 2.7.3 Simulation studies.........................................................................................62 2.7.4 The potential methods to cure ECI issued from studies...............................63 2.7.5 References.....................................................................................................64 2.8 ELECTRON CLOUD EFFECT IN THE LINEAR COLLIDERS......................................64 2.8.1 Introduction...................................................................................................65 2.8.2 Generation of the cloud................................................................................65 2.8.3 Thresholds for the development of the cloud: SEY Thresholds...................66 2.8.4 Head-Tail single-bunch and coupled bunch instabilities..............................67 2.8.5 Remedies for the electron-cloud build-up....................................................68 2.8.6 Miscellaneous discussions............................................................................69 2.8.7 Acknowledgments........................................................................................69 2.8.8 References.....................................................................................................69 2.9 ELECTRON-CLOUD BUILD-UP IN HADRON MACHINES...........................................70 2.9.1 Introduction...................................................................................................70 2.9.2 Primary sources of electrons and secondary electron emission....................71 2.9.3 Electron-cloud formation and dissipation.....................................................72 2.9.4 Acknowledgments........................................................................................75 2.9.5 References.....................................................................................................75 2.10 THEORY OF ELECTRON CLOUD INSTABILITY IN HIGH INTENSITY PROTON MACHINES..............................................................................................................77 2.10.1 Introduction....................................................................................77 2.10.2 Review of Data from the PSR [6-9]...............................................77 2.10.3 Coasting Beam Theory...................................................................78 2.10.4 Bunched Beam Theory...................................................................79 5 2.10.5 Nonlinear Space Charge.................................................................80 2.10.6 Other effects...................................................................................81 2.10.7 Conclusions....................................................................................82 2.10.8 References......................................................................................82 2.11 MEASUREMENTS OF ELECTRON CLOUD EFFECTS AT PSR*...............................83 2.11.1 Abstract..........................................................................................83 2.11.2 Introduction....................................................................................83 2.11.3 Recent studies on electron-cloud buildup......................................89 2.11.4 Some unresolved issues..................................................................97 2.11.5 Electron bursts................................................................................98 2.11.6 Beam response to weak kick........................................................102 2.11.7 Summary and Conclusions...........................................................104 2.11.8 Proposals for future work.............................................................105 2.11.9 Acknowledgements......................................................................106 2.11.10 Appendix: PSR Layout.................................................................106 2.11.11 References....................................................................................107 2.12 ELECTRON CLOUD IN THE SNS ACCUMULATOR RING......................................107 2.12.1 Introduction..................................................................................107 2.12.2 Multipacting mechanism..............................................................108 2.12.3 Important parameters related to multipacting..............................108 2.12.4 Multipacting inside dipole and quadrupole magnetic fields........110 2.12.5 Electron cloud clearing with solenoids and electrodes................111 2.12.6 References....................................................................................112 2.13 ELECTRON CLOUD STUDIES IN J-PARC AND KEK-PS.....................................114 2.13.1 Introduction..................................................................................114 2.13.2 Simulation studies........................................................................114 2.13.3 Experiments at the KEK 12 GeV Proton Synchrotron (KEK-PS)116 2.13.4 Conclusion....................................................................................119 2.13.5 References....................................................................................119 2.14 RHIC TWO STREAM EFFECTS...........................................................................120 2.14.1 Introduction..................................................................................120 2.14.2 Injection pressure rise...................................................................120 2.14.3 Transition pressure rise................................................................121 2.14.4 Scenario of 360 bunches in eRHIC..............................................122 2.14.5 References....................................................................................123 2.15 VACUUM LIMITATIONS DUE TO ELECTRON CLOUDS DURING THE RELATIVISTIC HEAVY ION COLLIDER RUN-4.............................................................................124 2.15.1 Introduction..................................................................................124 2.15.2 Beam current limitations..............................................................124 2.15.3 Experimental background limitations..........................................126 2.15.4 Summary......................................................................................127 2.15.5 Acknowledgements......................................................................128 2.15.6 References....................................................................................128 6 2.16 ELECTRON CLOUD OBSERVATIONS AT RHIC....................................................128 2.16.1 Introduction..................................................................................128 2.16.2 Experimental results.....................................................................130 2.16.3 Electron Cloud in the Interaction Regions...................................131 2.16.4 Possible cures...............................................................................134 2.16.5 Conclusion....................................................................................135 2.16.6 Acknowledgements......................................................................136 2.16.7 References....................................................................................136 2.17 MEASUREMENT OF ELECTRON CLOUD EFFECTS IN SPS...................................137 2.17.1 Introduction – SPS and LHC Issues.............................................137 2.17.2 Set up description - Specific results.............................................139 2.17.3 Beam related effects.....................................................................142 2.17.4 Room temperature observations...................................................144 2.17.5 Observations at cryogenic temperatures.......................................144 2.17.6 Epilogue: Open questions – Actions required..............................146 2.17.7 Acknowledgements......................................................................147 2.17.8 References....................................................................................147 2.18 ELECTRON-CLOUD EFFECTS IN THE LHC.........................................................150 2.18.1 Introduction..................................................................................150 2.18.2 Experiments in the LHC Injectors................................................150 2.18.3 Concerns for the LHC...................................................................151 2.18.4 Countermeasures..........................................................................153 2.18.5 Uncertainties.................................................................................154 2.18.6 References....................................................................................155 3 ADVANCED AND NOVEL ACCELERATORS............................................157 3.1 ACTIVITY AT KEK-ATF.....................................................................................157 3.1.1 Outline of ATF at KEK..............................................................................157 3.1.2 Emittance measurements at the EXT..........................................................158 3.1.3 Beam tuning in the DR...............................................................................158 3.1.4 Future plans................................................................................................159 3.1.5 References...................................................................................................160 3.2 LASER-ACCELERATOR RESEARCH ACTIVITY AT AIST.....................................161 3.2.1 Research......................................................................................................162 3.2.2 Experimental setup.....................................................................................162 3.2.3 Publications.................................................................................................163 3.3 RESEARCH ACTIVITY AT NUCLEAR ENGINEERING RESEARCH LABORATORY, UNIVERSITY OF TOKYO......................................................................................165 3.3.1 Experimental verification of new bunch compression, velocity bunching.165 3.3.2 Compact hard X-ray source based on X-band LINAC for medical use.....166 3.3.3 Electron acceleration via interaction between ultra-short intense laser pulse and gas jet...................................................................................................168 3.3.4 Laser plasma ion generation.......................................................................169 3.3.5 Time-resolved X-ray diffraction.................................................................169 7 3.3.6 Plasma simulation.......................................................................................169 3.3.7 References..................................................................................................170 3.3.8 Publications................................................................................................171 3.4 ACTIVITY AT HIROSHIMA UNIVERSITY..............................................................173 3.4.1 Space-Charge-Dominated Beam Physics...................................................173 3.4.2 Phase Transition of Ion Beams...................................................................174 3.4.3 Study of Compact Accelerators..................................................................175 3.4.4 Laser-Matter Interactions...........................................................................176 3.4.5 References..................................................................................................177 3.5 PROGRAM OF THE PARTICLE BEAM PHYSICS LABORATORY (PBPL)..............178 3.5.1 Some of the highlights of recent research include:....................................179 3.5.2 Contact information:...................................................................................181 3.5.3 Publications................................................................................................183 3.6 LASER GUIDING FOR HIGH ENERGY PLASMA ACCELERATORS...........................185 3.6.1 Introduction................................................................................................185 3.6.2 Laser wakefield in a capillary tube: model and numerical simulations...186 3.6.3 Laser guiding in a capillary tube: experimental results..............................189 3.6.4 Conclusion..................................................................................................190 3.6.5 Acknowledgements....................................................................................191 3.6.6 References..................................................................................................191 3.7 COMPUTATIONAL ACCELERATOR PHYSICS AT TECH-X CORPORATION...........192 3.7.1 Beam and plasma simulation codes VORPAL and OOPIC.......................192 3.7.2 Field-induced tunneling ionization.............................................................192 3.7.3 Simulating LWFA channels, in support of l’OASIS experiments.............193 3.7.4 Simulating high-power laser-pulses in overdense plasmas........................194 3.7.5 Simulating positron-driven PWFA experiments........................................194 3.7.6 Simulating electron cooling physics at relativistic energies for RHIC......195 3.7.7 Simulating electron emission from structures and related physics.............195 3.7.8 Particle tracking..........................................................................................195 3.7.9 Acknowledgements....................................................................................196 3.7.10 References....................................................................................196 4 RECENT DOCTORAL THESES....................................................................198 4.1 ANALYTICAL AND NUMERICAL STUDIES OF STOCHASTIC EFFECTS IN BEAM DYNAMICS............................................................................................................198 5 WORKSHOP AND CONFERENCE REPORTS...........................................199 5.1 13TH ICFA BEAM DYNAMICS MINI-WORKSHOP ON BEAM INDUCED PRESSURE RISW IN RINGS.....................................................................................................199 5.1.1 Summary of Pressure Rise Workshop........................................................199 5.1.2 Report of the Working Group on Electron Cloud Effects..........................203 5.1.3 Electron and ion desorption working group summary...............................211 8 5.2 31ST ICFA ADVANCED BEAM DYNAMICS WORKSHOP ON ELECTRON-CLOUD EFFECTS “ECLOUD04”.....................................................................................215 5.2.1 ECLOUD04 Workshop (Napa, California, April 19-23, 2004).................215 6 FORTHCOMING BEAM DYNAMICS EVENTS.........................................217 6.1 ICFA ADVANCED BEAM DYNAMICS WORKSHOPS............................................217 6.1.1 32nd ICFA Advanced Beam Dynamics Workshop on Energy Recovering Linacs, "ERL2004".....................................................................................217 6.1.2 33rd ICFA Advanced Beam Dynamics Workshop on High Intensity and High Brightness Hadron Beams "HB2004"................................................217 7 ANNOUNCEMENTS OF THE BEAM DYNAMICS PANEL......................218 7.1 ICFA BEAM DYNAMICS NEWSLETTER...............................................................218 7.1.1 Aim of the Newsletter.................................................................................218 7.1.2 Categories of Articles.................................................................................218 7.1.3 How to Prepare a Manuscript.....................................................................219 7.1.4 Distribution.................................................................................................219 7.1.5 Regular Correspondents..............................................................................220 7.2 ICFA BEAM DYNAMICS PANEL MEMBERS........................................................221 9 1 Foreword 1.1 From the Chairman Weiren Chou, Fermilab mail to: [email protected] 1.1.1 Changes in the Panel At the February 2004 meeting in Paris, ICFA approved five new Panel members: Yoshiharu Mori (KEK), Ingo Hofmann (GSI), Miguel Furman (LBNL), In Soo Ko (POSTECH) and Rainer Wanzenberg (DESY). These are well-known physicists in the global accelerator community. Please join me to welcome them on board. Yoshi replaced me as the new Chair of the ICFA Working Group on High Intensity and High Brightness Hadron Beams. Rainer replaced Helmut Mais to take over the responsibility of printing and distributing the ICFA BD Newsletter in Europe and Africa. John Jowett (CERN) and Helmut Mais (DESY) resigned from the panel. John did excellent service as the Panel Chair in the past several years. Helmut made great contributions to the panel, in particular for his work on the Newsletter. On behalf of the Panel, I'd like to give them my sincere and heartfelt thanks. The Panel now has 19 members, who are listed at the end of this Newsletter. The membership is well balanced among three regions: 6 from Asia, 6 from Europe and 7 from North America. The Panel also has 4 working groups, with each chaired by a Panel member: • Future Light Sources (Chair: K-J. Kim) • High Luminosity e+e- Colliders (Chair: C. Biscari) • High Intensity and High Brightness Hadron Beams (Chair: Y. Mori) • Remote Experiments in Accelerator Physics (Chair: D. Rice) For technical reasons the Panel’s web site has moved to a new address: http://www-bd.fnal.gov/icfabd/ It has links to the main ICFA web site as well as to the sites of the 4 working groups. Ernie Malamud, a retired senior physicist from Fermilab, serves as the web master. 1.1.2 Panel activities in 2004: It is planned to publish three issues of the ICFA BD Newsletter this year: No. 33 (this issue, editors K. Ohmi and M. Furman), No. 34 (August, editor D. Rice) and No. 35 (December, editor C. Biscari). Also scheduled are three ICFA Advanced Beam Dynamics Workshops (ABDW): the 31st titled ECLOUD04 (April 19-23 in Napa, California, U.S.A., chaired by M. Furman), the 32nd titled ERL2004 (October 10-14, JLab, Virginia, U.S.A., co-chaired by S. Chattopadhyay and L. 10 Merminga), and the 33rd titled HB2004 (October 18-22, Bensheim, Germany, co-chaired by I. Hofmann and J-M. Lagniel). Each working group also plans to have one or more ICFA mini-workshops. These mini- workshops have proved to be effective and productive, because they are well focused, easy to organize and the publication of formal proceedings is not required. In addition to these activities, the Panel is working on a new project: the compilation of a new Accelerator Catalogue. The existing one was published more than a decade ago and needs to be updated. The new one will be published both in paper copy and online. The following five Panel members have agreed to take lead responsibilities on this project: • e+e- Colliders – C. Biscari (LNF-INFN) • Light sources (including FELs) – K-J. Kim (ANL) • Ion accelerators – I. Hofmann (GSI) • Cyclotrons and FFAGs – Y. Mori (KEK) • Proton machines – W. Chou (Fermilab) We have also invited J.-F. Ostiguy (Fermilab) to be the technical adviser for this project. The scheduled completion date is January 2005. 1.1.3 ICFA and the Linear Collider In Febrary 2004, ICFA issued a Second Statement on Linear Colliders, which is included in this issue (Section 1.3). In the present Linear Collider organization structure, ICFA is the governing body and oversees the work of the International Linear Collider Steering Committee (ILCSC). This will remain the case until a group of governments establish an oversight board to take over the leadership from ICFA. On the ICFA main web page: http://www.fnal.gov/directorate/icfa/icfa_home.html you can find all the important documents regarding Linear Colliders. 1.1.4 Other issues At the February ICFA meeting, attended by about fifteen lab directors in addition to the ICFA members and Panel Chairs, there was a discussion about how to support panel activities, such as attending ICFA meetings and workshops, organizing the workshops, and printing and distributing the Newsletter. There was general agreement that the lab directors should recognize the importance of support for these activities and give favourable consideration to requests to participate in these activities by their staff members. There have been a number of complaints on the visa problems experienced by foreign visitors to the U.S. In particular, ICFA workshop organizers often find it difficult to have invited speakers from China or Russia if the workshop takes place in the U.S. Although this is a problem for more than just accelerator scientists, ICFA has taken steps to address this issue in conjunction with the American Physical Society (APS) and other science organizations. The problems have been reported to the White House Office of Science and Technology Policy (OSTP). It is our hope that the present U.S. visa policy will be changed soon and international collaboration in science and technology between the U.S. and other countries can return back to normal.