| Paper |
Title |
Page |
| WEAX01 |
Resonance trapping due to space charge and synchrotron motion, in theory, simulations, and experiments
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167 |
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- G. Franchetti, I. Hofmann
GSI, Darmstadt
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With the development of high intensity accelerator, the role of space charge effect in a nonlinear lattice gained special attention, as in the FAIR project at GSI, where long term storage of high intensity beams is required. The simultaneous presence of space charge and a nonlinear lattice creates an unprecedented challenge for ring designers as well as a new area of studies in beam physics. We present our understanding of the effect of space charge and chromaticity on the nonlinear beam dynamics of a bunched beam.
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| WEAX02 |
Space charge simulation of J-PARC main ring
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177 |
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- A. Y. Molodozhentsev, M. Tomizawa
KEK, Ibaraki
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The space charge effect in combination with the intrinsic field nonlinearity like the sextupole nonlinearity, used for the chromaticity correction, could lead to significant particle losses in a high beam intensity proton machine. For J-PARC Main Ring (MR) the total particle losses at the ring’s collimator should be less than 1% from the expected maximum beam power of 45kW at the injection energy of 3GeV. To keep the particle losses during the injection process within the required limit it is necessary to optimize the beam parameters from the injector (J-PARC RCS), the collimator aperture of the beam-line from RCS to MR and the collimator aperture of MR. Influence of the structure and non-structure high-order resonances for different working points is discussed. The budget of the beam losses for different MR commissioning scenario is presented.
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| WEAX03 |
Space charge neutralization and its dynamic effects
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187 |
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- R. Duperrier, N. Pichoff, D. Uriot
CEA, Gif-sur-Yvette
- A. BenIsmail
LLR, Palaiseau
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High-power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. In this low energy part, the space charge self force, induced by a high intensity beam, has to be carefully controlled. This nonlinear force can generate a large and irreversible emittance growth of the beam. To reduce the space charge (SC), neutralization of the beam charge can be done by capturing some particles of the ionised residual gas in the vacuum chamber. This space charge compensation (SCC) regime complicates the beam dynamics study. This contribution aims to modelize the beam behavior in such a regime and to give order of magnitude to the linac designer for the neutralization rise time and the induced emittance growth.
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| WEAX04 |
High Intensity Cyclotron Simulations: Towards Quantitative Predictions
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202 |
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- A. Adelmann, S. R.A. Adam, M. Humbel, P. A. Schmelzbach
PSI, Villigen
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PSI operates the most powerful cyclotron worldwide to the benefit of a multi-user, cross-disciplinary research facility. The accelerator complex consists of a Cockcroft-Walton pre-injector, a 72-MeV separated sector injector cyclotron and a 590-MeV separated sector Ring Cyclotron. A beam current of 1.9 mA is routinely extracted from the Ring Cyclotron overall absolute losses are below 1·10-3. The facility has a considerable potential for further improvements, an ongoing upgrade project aims at a beam current of 3 mA. The purpose of our multi-scale three-dimensional parallel code and methods development is to make the step from qualitative to quantitative predictions. Their simulation requires the accurate three-dimensional modeling of large and complicated accelerator structures including space charge, beam lines, collimation, and in the future secondary effects. We will show methods, both numerically and computational, that we use presently and give an overview on future directions. Measurements from the cyclotrons and beamlines will be compared with simulations carried out in the frame of the high intensity upgrade program.
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| WEAX05 |
Space-Charge Beam Physics Research at the University of Maryland Electron Ring (UMER)*
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218 |
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- S. Bernal, B. L. Beaudoin, D. W. Feldman, R. Feldman, R. B. Fiorito, T. F. Godlove, I. Haber, R. A. Kishek, P. G. O'Shea, C. Papadopoulos, B. Quinn, D. Stratakis, K. Tian, C. Tobin, M. Walter
IREAP, College Park, Maryland
- M. Reiser
University Maryland, College Park, Maryland
- D. F. Sutter
HENP, SW Washington
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The University of Maryland electron ring (UMER) is a low-energy, high current recirculator for beam physics research with relevance to any applications that rely on intense beams of high quality. We review the space-charge physics issues, experimental and computational investigations, which are currently being conducted at the UMER facility. The physics issues cover a broad range, but we focus on transverse beam dynamics: halo formation, strongly asymmetric beams, Montague resonances, equipartitioning, etc. Furthermore, we report on recent developments in experiments, simulations, and improved diagnostics for space-charge dominated beams.
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| WEAX06 |
Measurements and Synergia simulations of emittance dilution at the Fermilab Booster.
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236 |
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- P. Spentzouris
Fermilab, Batavia, Illinois
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We present a study of the beam evolution in the Fermilab Booster operating both under nominal conditions and in the vicinity of the sum resonance for different beam currents. We simultaneously recorded the horizontal and vertical beam profiles using the Ion Profile Monitor and beam current. Our analysis extracted 2-D emittances and beam shape information from the IPM data. We compare the results with Synergia simulations including 3-D space charge and higher-order optics to analyze and interpret the experimental results.
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