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Space Charge and Optics Studies for High-Intensity Machine

Profile image of M. GiovannozziM. Giovannozzi

2005

https://doi.org/10.5170/CERN-2005-006.25
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Abstract

In the FAIR [1] facility planned at GSI high space charge may play an important role for limiting the foreseen nominal machine performance. In the SIS100, bunches with tuneshift as large as ≈ 0.2 should be stored for hundred thousand turns keeping the loss budget within few percent to avoid quenching of superconducting magnets and vacuum degradation. Usually, design criteria to meet these beam dynamics constraints rely on quantities such as dynamic aperture or nonlinear acceptance. The presence of space charge in a nonlinear lattice sets, however, new challenges to beam loss control and requires an effort to understand unexplored leading beam loss mechanisms. In this context beam loss studies for a high intensity bunched beam have been performed at the CERN-Proton Synchrotron. We discuss the experimental results and propose a mechanism for explaining the observed beam loss. We then apply to the SIS100 what we have learnt from CERN-Proton Synchrotron measurements and discuss its consequences.

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Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge
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References (29)

  1. W. Henning, these Proceeding.
  2. A. Schoch, (1958), CERN Report, CERN 57-23.
  3. A. W. Chao and M. Month, Nucl. Instrum. Meth., 121, 129- 138 (1974).
  4. T. Satogata et al., Phys. Rev. Lett., 68, 1838-1841 (1992).
  5. A. W. Chao and M. Month, Nucl. Instrum. Meth., 133, 405- 408 (1976).
  6. R. Cappi and M. Giovannozzi, Phys. Rev. Lett., 88, 104801 (2002).
  7. M. Giovannozzi et al., these Proceedings.
  8. Conceptual Design Report, http://www.gsi.de/GSI- Future/cdr/.
  9. P. Spiller, these Proceeding.
  10. A. Bazzani et al., ICFA-HB2004, to be published as AIP proc.
  11. G. Franchetti and I. Hofmann, AIP Conf. Proc., 642, 260- 262 (2002).
  12. J. Struckmeier, Phys. Rev., E54, 830-837 (1996).
  13. G. Franchetti, I. Hofmann, M. Giovannozzi, M. Martini and E. Metral, Phys. Rev. ST Accel. Beams, 6, 124201 (2003).
  14. G. Franchetti and I. Hofmann, p. 1975, EPAC 2004.
  15. E. Metral et al., ICFA-HB2004, to be published as AIP proc.
  16. I. Hofmann et al., ICFA-HB2004, to be published as AIP proc.
  17. I. Hofmann, G. Franchetti, M. Giovannozzi, M. Martini and E. Metral, p.129, PAC 2003.
  18. A. Orzhekhovskaya and G. Franchetti, p. 1972, EPAC 2004.
  19. R. Cappi et al., p. 2913, PAC 2003.
  20. R. Bartolini, A. Bazzani, M. Giovannozzi, W. Scandale, and E. Todesco, Part. Accel., 52, p. 147-177, (1996).
  21. R. Hasse, private comunication.
  22. C. Muehle, private comunication.
  23. K. Blasche, private comunication.
  24. P. Krejcik, p. 1278, PAC 1987.
  25. M. Giovannozzi, AIP Conf. Proc., 693, 26-31 (2004).
  26. M. Giovannozzi, W. Scandale, and E. Todesco, Phys. Rev., E57, 3432-3443 (1998).
  27. E. Todesco, M. Giovannozzi, Phys. Rev., E53, 4067-4076 (1996).
  28. J. P. Koutchouk, p. 372, PAC 1999.
  29. G. Moritz, private comunication.

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