Development of an in Situ 3He NSF Using SEOP Technique with an Evaluation System for the Pulsed Neutron Source

A 3He spin filter is a useful device for polarizing a neutron beam. We are developing the 3He spin filters for users of the material and life science facility of the Japan Proton Accelerator Research Complex (J‑PARC). An in situ SEOP system with a 3He polarization evaluation system using nuclear magnetic resonance (NMR) method of adiabatic fast passage and electron paramagnetic resonance (EPR) was developed. We conducted an experiment on the neutron beam line BL10 (NOBORU) of J-PARC to confirm the consistency of 3He polarization, estimated using the neutron transmission, NMR and EPR. The polarization of 3He, evaluated using the different methods, was consistent and the evaluation system operated normally for about 6 h.