Development of compact laser optics for an in-situ spin-exchange optical pumping He neutron spin filter

Oku, Takayuki   ; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji ; Hiroi, Kosuke  ; Shinohara, Takenao   ; Sakaguchi, Yoshifumi*; Ino, Takashi*; Oyama, Kenji*; Chang, L.-J.*; Nakamura, Mitsutaka   ; Suzuki, Junichi*; Shimizu, Hirohiko*; Aizawa, Kazuya  ; Arai, Masatoshi; Endo, Yasuo; Kakurai, Kazuhisa

The He NSF is effective even for neutrons with energy higher than several-tens-meV, so that it will be useful for the study of high-energy magnetic excitation. Since the He NSF can also cover a large solid angle and polarize neutrons without deflecting them from their original course, it is suitable for the analyzer for SANS instruments and reflectometers. In order to apply the He NSF to experiments at a 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 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 He NSF. The design and performance of the in-situ SEOP He NSF will be then presented, and its possible application will be discussed.