Studies of E-Cloud Build up for the FNAL Main Injector and for theLHC
We present a summary of recent simulation studies of the electron-cloud (EC) build-up for the FNAL MI and for the LHC. In the first case we pay particular attention to the dependence on bunch intensity N{sub b} at injection energy assuming the nominal bunch spacing t{sub b} = 19 ns, and we focus on the dipole magnets and field-free regions. The saturated value of the average EC density shows a clear threshold in N{sub b} beyond which the beam will be approximately neutralized on average. For the case of the LHC we limit our discussion to arc dipoles at collision energy, and bunch spacings t{sub b} = 25 ns or t{sub b} = 75 ns. The main variables exercised in this study are N{sub b} and the peak value of the secondary emission yield (SEY) {delta}{sub max}. For t{sub b} = 25 ns we conclude that the EC power deposition is comfortably below the available cooling capacity of the cryogenic system if {delta}{sub max} is below {approx} 1.2 at nominal N{sub b}. For t{sub b} = 75 ns, the EC power deposition is insignificant. As a byproduct of this exercise, we reach a detailed understanding of the significant role played by the backscattered secondary electrons. This article summarizes the results, an slightly extends the discussions, presented in Refs. 1 and 2.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of High EnergyPhysics, Officeof Science Undergraduate Laboratory Internship Program,US LHC Accelerator Research Program
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 888977
- Report Number(s):
- LBNL-60512; R&D Project: 455301; BnR: KA1501020; TRN: US0604354
- Resource Relation:
- Conference: 397th ICFA advanced beam dynamics workshop - Highintensity high brightness hadron beams, Tsukuba, Japan, May 29 - June 2,2006
- Country of Publication:
- United States
- Language:
- English
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