| Paper |
Title |
Page |
| THPCH004 |
Space Charge Induced Resonance Trapping in High-intensity Synchrotrons
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2790 |
| |
- G. Franchetti, I. Hofmann
GSI, Darmstadt
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With the recent development of high-intensity circular accelerators, the simultaneous presence of space charge and lattice nonlinearities has gained special attention as possible source of beam loss. In this paper we present our understanding of the role of space charge and synchrotron motion as well as chromaticity for trapping of particles into the islands of nonlinear reonances. We show that the three effects combined can lead to significant beam loss, where each individual effect leads to small or negligible loss. We apply our findings to the SIS100 of the FAIR project, where the main source of field nonlinearities stems from the pulsed super-conducting dipoles, and the beam dynamics challenge is an extended storage at the injection flat-bottom, over almost one second, together with a relatively large space charge tune shift.
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| THPCH005 |
Considerations for the High-intensity Working Point of the SIS100
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2793 |
| |
- G. Franchetti, O. Boine-Frankenheim, I. Hofmann, V. Kornilov, P.J. Spiller, J. Stadlmann
GSI, Darmstadt
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In the FAIR project the SIS100 synchrotron is foreseen to provide high-intensity beams of U 28+, including slow extraction to the radioactive beam experimental area, as well as high-intensity p beams for the production of antiprotons. In this paper we discuss the proposal of three different working points, which should serve the different needs: (1) a high intensity working point for U28+; (2) a slow extraction working point (also U28+); (3) a proton operation working point to avoid transition crossing. The challenging beam loss control for all three applications requires a careful account of the effects of space charge, lattice nonlinearities and chromaticity, which will be discussed in detail in this paper. Since tunes are not split by an integer and the injected emittances are different, the Montague stop-band needs to be avoided. Moreover, final bunch compression for the U beam requires a sufficiently small momentum spread, and the risk of transverse resisitive wall instabilities poses further limitations on our choice of working points.
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| THPCH006 |
Scaling Laws for the Montague Resonance
|
2796 |
| |
- I. Hofmann, G. Franchetti
GSI, Darmstadt
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The space-charge-driven Montague resonance is a source of emittance coupling in high-intensity accelerators with un-split tunes. Here we present scaling laws for the stop-band widths, growth rates and crossing behavior of this fourth order resonance. Our results on the coupling can be applied to circular machines as well as to linear accelerators. Based on self-consistent coasting beam simulation we show that for slow crossing of the stop-bands a strong directional dependence exists: in one direction the exchange is smooth and reversible, in the other direction it is discontinuous. We also discuss the combined effect of the Montague resonance and linear coupling by skew quadrupoles.
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| THPCH018 |
Resonance Trapping, Halo Formation and Incoherent Emittance Growth due to Electron Cloud
|
2820 |
| |
- E. Benedetto, E. Benedetto
Politecnico di Torino, Torino
- G. Franchetti
GSI, Darmstadt
- G. Rumolo, F. Zimmermann
CERN, Geneva
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The pinched electron cloud introduces a tune shift along the bunch, which together with synchrotron motion, leads to a periodic crossing of resonances. The resonances are excited by the longitudinal distribution of the electron cloud around the storage ring. We benchmark the PIC code HEADTAIL against a simplified weak-strong tracking code based on an analytical field model, obtaining an excellent agreement. The simplified code is then used for exploring the long term evolution of the beam emittance, and for studying more realistic lattice models. Results are presented for the CERN SPS and the LHC.
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| WEPCH141 |
Accelerator Physics Code Web Repository
|
2254 |
| |
- F. Zimmermann, R. Basset, E. Benedetto, U. Dorda, M. Giovannozzi, Y. Papaphilippou, T. Pieloni, F. Ruggiero, G. Rumolo, F. Schmidt, E. Todesco
CERN, Geneva
- D.T. Abell
Tech-X, Boulder, Colorado
- R. Bartolini
Diamond, Oxfordshire
- O. Boine-Frankenheim, G. Franchetti, I. Hofmann
GSI, Darmstadt
- Y. Cai, M.T.F. Pivi
SLAC, Menlo Park, California
- Y.H. Chin, K. Ohmi, K. Oide
KEK, Ibaraki
- S.M. Cousineau, V.V. Danilov, J.A. Holmes, A.P. Shishlo
ORNL, Oak Ridge, Tennessee
- L. Farvacque
ESRF, Grenoble
- A. Friedman
LLNL, Livermore, California
- M.A. Furman, D.P. Grote, J. Qiang, G.L. Sabbi, P.A. Seidl, J.-L. Vay
LBNL, Berkeley, California
- D. Kaltchev
TRIUMF, Vancouver
- T.C. Katsouleas
USC, Los Angeles, California
- E.-S. Kim
PAL, Pohang, Kyungbuk
- S. Machida
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
- J. Payet
CEA, Gif-sur-Yvette
- T. Sen
Fermilab, Batavia, Illinois
- J. Wei
BNL, Upton, Long Island, New York
- B. Zotter
Honorary CERN Staff Member, Grand-Saconnex
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In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans.
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