Electron-Cloud Build-Up Simulations for the FNAL Main Injector [electronic resource].
- Published:
- Berkeley, Calif. : Lawrence Berkeley National Laboratory, 2008.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Additional Creators:
- Lawrence Berkeley National Laboratory and United States. Department of Energy. Office of Scientific and Technical Information
Access Online
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Summary:
- We present a summary on ongoing simulation results for the electron-cloud (EC) buildup in the context of the proposed FNAL Main Injector (MI) intensity upgrade effort [1]. Most of the results presented here are for the field-free region at the location of the retarding field analyzer (RFA) electron detector [2-4]. The primary input variable we exercise is the peak secondary electron yield (SEY) δ{sub max}, which we let vary in the range 1.2 ≤ δ{sub max} ≤ 1.7. By combining our simulated results for the electron flux at the vacuum chamber wall with the corresponding RFA measurements we infer that 1.25 ≈< δ{sub max} ≈< 1.35 at this location. From this piece of information we estimate features of the EC distribution for various fill patterns, including the average electron number density n{sub e}. We then compare the behavior of the EC for a hypothetical RF frequency f{sub RF} = 212 MHz with the current 53 MHz for a given total beam population N{sub tot}. The density n{sub e} goes through a clear threshold as a function of N{sub tot} in a field-free region. As expected, the higher frequency leads to a weaker EC effect: the threshold in N{sub tot} is a factor ≈ 2 higher for f{sub RF} = 212 MHz than for 53 MHz, and ne is correspondingly lower by a factor ≈ 2 when N{sub tot} is above threshold. We briefly describe further work that needs to be carried out, sensitivities in the calculation, and puzzles in the results that remain to be addressed.
- Report Numbers:
- E 1.99:lbnl-1402e
lbnl-1402e - Other Subject(s):
- Note:
- Published through SciTech Connect.
08/25/2008.
"lbnl-1402e"
42nd ICFA Advanced Beam Dynamics Workshop on High-Intensity, High-Brightness Hadron Beam, Nashville, TN, Aug 25-29, 2008.
Furman, Miguel .A.
Accelerator&
Fusion Research Division - Funding Information:
- DE-AC02-05CH11231
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