Development of an in-situ SEOP 3He Neutron Spin Filter for Magnetic Imaging Techniques

We have been developing a 3He neutron spin filter (NSF) using a spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. A high-energy polarized neutron beam, which is more difficult to produce with commonly used magnetic supermirror-based polarizers, is an effective probe for magnetic imaging techniques, particularly in the case of strong magnetic fields. Additionally, an in-situ SEOP system enables us to produce a polarized neutron beam with stable polarization, which is big advantage for experiments with long measurement times. In this study, we installed two in-situ SEOP systems as a neutron spin polarizer and analyzer providing a stable high-energy polarized neutron beam over several days.