Fabrication of wide angle polarized 3He cells in China Spallation Neutron Source (CSNS)

As part of ongoing upgrade efforts in the China Spallation Neutron Source (CSNS), the neutron polarization team has been actively working on the fabrication procedure of 3He-based neutron spin filters having large angle coverage. We report substantial success in blowing and filling the first wide-angle 3He glass cells in China. The contained 3He gas is polarized on our off-situ spin-exchange optical pumping system. The polarization signals of 3He are measured via the free induction decay and the electron paramagnetic resonance techniques. The best measured lifetime and polarization are 236.3 ± 2.5 h and 65%, respectively.