A preliminary assessment of the electron cloud effect for the FNALmain injector upgrade

Furman, M.A.

Lawrence Berkeley National Laboratory

关键词: Clouds;    Secondary Emission Electron-Cloud Effect Main Injector;    43 Particle Accelerators;    Computerized Simulation;    Electrons;   

DOI  :  10.2172/861024
RP-ID  :  LBNL--57634
RP-ID  :  DE-AC02-05CH11231
RP-ID  :  861024

美国|英语

来源: UNT Digital Library

【 摘 要 】

We present results from a preliminary assessment, via computer simulations, of the electron cloud density for the FNAL main injector upgrade at injection energy. Assuming a peak value for secondary emission yield {delta}{sub max} = 1.3, we find a threshold value of the bunch population, N{sub b,th} {approx} 1.25 x 10{sup 11}, beyond which the electron-cloud density {rho}{sub e} reaches a steady-state level that is {approx}10{sup 4} times larger than for N{sub b} < N{sub b,th}, essentially neutralizing the beam, and leading to a tune shift {approx}0.05. Our investigation is limited to a field-free region and to a dipole magnet, both of which yield similar results for both N{sub b,th} and the steady-state value of {rho}{sub e}. Possible dynamical effects from the electron cloud on the beam, such as emittance growth and instabilities, remain to be investigated separately.