CEPC positron source design

Abstract

PurposeCircular Electron Positron Collider (CEPC) is a 100-km-ring e+ e− collider for a Higgs factory. The injector is composed of a 10-GeV Linac and a 120-GeV Booster. The CEPC Linac is a normal conducting S-band Linac with frequency of 2860\xa0MHz providing electron and positron beams at an energy up to 10\xa0GeV with 100\xa0Hz repetition frequency. The positron source is the most important part of the CEPC Linac, and the bunch charge of positron beam within some cut-off condition should be larger than 3 nC.MethodsThe positron source of CEPC is composed of a target, a flux concentrator, a capture section, a pre-accelerating section and a beam separation system. Higher positron yield and capture efficiency are the design goal. Based on simulation, the design will be presented and discussed in detail.ResultThe positron yield at the PSPAS exit is larger than 0.55, and the normalized rms emittance is 2370\xa0mm-mrad with a strict cut-off condition. The detailed simulation results will be presented.ConclusionsThe design of the positron source including positron production and capture will be presented and can meet the requirements.