System design and measurements of flux concentrator and its solid-state modulator for CEPC positron source

Abstract

Positron sources are one of the most important components of the injector of a circular electron positron collector (CEPC). The CEPC is designed as an e+e− collider for a Higgs factory. Its accelerator system is composed of 100-km-long storage rings and an injector. The design goal of the positron source is to obtain positron beams with a bunch charge of 3 nC. The flux concentrator (FC) is one of the cores of the positron source. This paper reports the design, development, and measurements of an FC prototype system. The prototype includes an FC and an all-solid-state high-current pulse modulator. Preliminary tests show that the peak current on the FC can reach 15.5 kA, and the peak magnetic field can reach 6.2\xa0T. The test results are consistent with the theoretical simulation. The FC system fulfills the requirements of the CEPC positron source as well as provides a reference for the development of similar devices both domestically and abroad.