Optimization of the BEPC Positron Source

Abstract：

Based upon Monte Carlo simulation and particle tracing, the positron source of the BEPC is designed and the predicted performance is compared with the experimental measurement. It shows that they are in good agreement. Important conclusions are drawn from the study presented in this paper:the increase in the electron gun current up to 10 A is beneficial in spite of the deterioration effect on the beam spot size at the target; positron current increases with the bridge coil and solenoid current and the position of matching field peak relative to the target; the existence of two injection phases and their significance; the electrons and positrons from the target do not have to be separated and the R. F. separator is not necessary, etc. The above results are important to the tune-up and operation of the BEPC, and provide a useful reference for the future design of positron accelerators.