Development of a Spin-Exchange Optical Pumping-Based Polarized 3He System at the China Spallation Neutron Source(CSNS)

Polarized 3 He neutron spin filters(NSFs)can be used as a vital tool for neutron polarization production and analysis.The China Spallation Neutron Source(CSNS),as one of the major neutron facilities in China,has committed resources to the development of a polarized 3He NSF program to support its growing polarized neutron research.A spin-exchange optical pumping(SEOP)-based polarized 3He system and other necessary hardware for NSF transport has been recently developed.The performance of the system is benchmarked using an in-house developed cell named"Trident".Neutron beam measurements yield a 3He polarization of 77％with over 200 h of on-beam relaxation time.Combining this newly developed SEOP system with the recently reported cell fabrication station,CSNS is now capable of the fully self-sustained production of 3He NSFs that shall support its future neutron polarization research.