| Paper |
Title |
Page |
| MOPKF084 |
Beam Instabilities in Lepton Ring of eRHIC
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515 |
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- D. Wang, M. Farkhondeh, C. Tschalaer, J. Van der Laan, F. Wang, A. Zolfaghari, T. Zwart
MIT/BLAC, Middleton, Massachusetts
- M. Blaskiewicz, Y. Luo, L. Wang
BNL, Upton, Long Island, New York
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The eRHIC is a high luminosity lepton-hadron collider planned to be built in Brookhaven National Lab, Upton, New York, USA. The lepton machine of eRHIC is a completely newly designed machine complex to provide highly polarized lepton beams at up to 10 GeV energy for the high luminosity lepton-hadron collisions. This paper decribes major issues of collective effects in this lepton storage ring. Besides conventional impedance-driven instabilities, the electron cloud effects in positron operation and fast beam-ion effects in electron operation are of major conserns. The analytical and numerical estimats for major collective effects are made with different machine operation conditions.
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| MOPLT176 |
Mechanism of Electron Multipacting with a Long Bunch Proton Beam
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938 |
| |
- L. Wang, M. Blaskiewicz, J. Wei
BNL, Upton, Long Island, New York
- R.J. Macek
LANL/LANSCE, Los Alamos, New Mexico
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The mechanism of electron multipacting in long bunched proton machine has been quantitatively described by the electron energy gain and electron motion. Some important parameters related to electron multipacting are investigated in detail. It is proved that multipacting is sensitive to beam intensity, longitudinal beam profile shape and transverse beam size. Agreement is achieved among our analysis, simulation and experiment.
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| WEPLT183 |
Clearing of Electron Cloud in SNS
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2245 |
| |
- L. Wang, Y.Y. Lee, D. Raparia, J. Wei, S.Y. Zhang
BNL, Upton, Long Island, New York
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In this paper we describe a mechanism using the clearing electrodes to remove the electron cloud in the Spallation Neutron Source (SNS) accumulator ring, where strong multipacting could happen at median clearing fields. A similar phenomenon was reported in an experimental study at Los Alamos laboratory's Proton Synchrotron Ring (PSR). We also investigated the effectiveness of the solenoid's clearing mechanism in the SNS, which differs from the short bunch case, such as in B-factories.
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| WEPLT184 |
Preliminary Estimation of the Electron Cloud in RHIC
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2248 |
| |
- L. Wang, P. He, J. Wei
BNL, Upton, Long Island, New York
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Electron cloud due to beam induce multipacting is suspected to be one of the source of pressure rises in RHIC. This paper estimates the possible electron cloud in RHIC. Various parameters related electron multipacting has been investigated.
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| MOPLT178 |
RHIC Pressure Rise
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944 |
| |
- S.Y. Zhang, J. Alessi, M. Bai, M. Blaskiewicz, P. Cameron, K.A. Drees, W. Fischer, R.P. Fliller III, D. Gassner, J. Gullotta, P. He, H.-C. Hseuh, H. Huang, U. Iriso, R. Lee, Y. Luo, W.W. MacKay, C. Montag, B. Oerter, S. Peggs, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, L. Smart, P. Thieberger, D. Trbojevic, J. Van Zeijts, L. Wang, J. Wei, K. Zeno
BNL, Upton, Long Island, New York
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Beam induced pressure rise remains an intensity limit at the RHIC for both heavy ion and polarized proton operations. The beam injection pressure rise at warm sections has been diagnosed due to electron cloud effect. In addition, pressure rise of heavy ion operation at the beam transition has caused experiment background problem in deuteron-gold run, and it is expected to take place in gold-gold run at high intensities. This type of pressure rise is related to beam momentum spread, and the electron cloud seems not dominant. Extensive approaches for both diagnosis and looking-for-remedies are undergoing in the current gold operation, RUN 4. Results of beam scrubbing, NEG pipe in RHIC ring, beam scraping test of ion desorption, beam momentum effect at the transition, beam gap effect, solenoid effect, and NEG pipe ion desorption test stand will be presented.
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| THPLT017 |
Review and Comparison of Simulation Codes Modeling Electron-Cloud Build Up and Instabilities
|
2499 |
| |
- F. Zimmermann, E. Benedetto, F. Ruggiero, D. Schulte
CERN, Geneva
- G. Bellodi
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
- M. Blaskiewicz, L. Wang
BNL, Upton, Long Island, New York
- Y. Cai, M.T.F. Pivi
SLAC, Menlo Park, California
- V.K. Decyk, W. Mori
UCLA, Los Angeles, California
- M.A. Furman
LBNL/AFR, Berkeley, California
- A.F. Ghalam, T. Katsouleas
USC, Los Angeles, California
- K. Ohmi, S.S. Win
KEK, Ibaraki
- G. Rumolo
GSI, Darmstadt
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Several computer codes written at various laboratories are employed for modelling the generation and the consequences of an electron cloud. We review the most popular of these programs, which simulate either the build of an electron cloud or the instabilities it produces, and we compare simulation results for identical, or similar, input parameters obtained from the various codes.
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