We have been developing a 3He neutron spin filter (NSF) for efficient utilization of pulsed neutrons, since it can polarize neutrons effectively in a wide energy range. In order to apply the 3He-NSF to experiments at an intense pulsed neutron experimental facility such as the J-PARC, it is important to make the system stable and easy to setup and operate, because the system is located inside a radiation shield for high energy gamma ray and neutrons. In this study, we have developed compact laser optics with a volume holographic grating (VHG) element for a spin-exchange optical pumping (SEOP) system, and composed an in-situ SEOP 3He-NSF. Current status in the development and application of the in-situ SEOP 3He-NSF at J-PARC is reported.
