Electron-cloud instabilities and beam-induced multipacting in the LHC and in the VLHC
In the beam pipe of the Large Hadron Collider (LHC), photoemission and secondary emission give rise to a quasi-stationary electron cloud, which is established after a few bunch passages. The response of this electron cloud to a transversely displaced bunch resembles a short-range wakefield and can cause a fast instability. In addition, beam-induced multipacting of the electrons may lead to an enhanced gas desorption and an associated pressure increase. In this paper the authors report preliminary simulation results of the electron-cloud build-up both in a dipole magnet and in a straight section of the LHC at top energy. The effective wakefield created by the electron cloud translates into an instability rise time of about 40 ms horizontally and 500 ms vertically. This rise time is not much larger than that of the resistive-wall instability at injection energy. Similar simulation studies show that the instability rise time for the proposed Very Large Hadron Collider (VLHC) is about 3--4 s in both transverse planes. The smaller growth rate in the VLHC, as compared with the LHC, is primarily due to the much lower bunch population.
- Research Organization:
- Stanford Univ., Stanford Linear Accelerator Center, CA (US)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (US); European Organization for Nuclear Research, Geneva (Switzerland) (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 674790
- Report Number(s):
- SLAC-PUB-7664; CONF-970792-; ON: DE98059149; TRN: US200305%%545
- Resource Relation:
- Other Information: Supercedes report DE98059149; PBD: Oct 1997; PBD: 1 Oct 1997
- Country of Publication:
- United States
- Language:
- English
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