Development of a compact laser optics system for an in-situ SEOP He neutron spin filter

Oku, Takayuki   ; Hayashida, Hirotoshi; Sakai, Kenji ; Shinohara, Takenao   ; Nakamura, Mitsutaka   ; Arai, Masatoshi; Endo, Yasuo; Kakurai, Kazuhisa; Kira, Hiroshi*; Sakaguchi, Yoshifumi*; Suzuki, Junichi*; Arimoto, Yasushi*; Ino, Takashi*; Oyama, Kenji*; Hiraka, Haruhiro*; Shimizu, Hirohiko*

We have been developing an SEOP polarized He neutron spin filter to apply it to pulsed neutron experiments. The He based neutron polarizer is useful in experiments such as polarized neutron scattering experiments in a wide q-range, inelastic scattering experiment with high energy magnetic and phonon excitation, magnetic field imaging and etc, since it is effective for neutrons in a wide energy range. To introduce the SEOP polarized He neutron spin filter into the instruments of the pulsed neutron facility such as J-PARC, it is important to make the system compact and stable, because the system is located inside thick and bulky radiation shields for high energy ray and neutrons. In this study, we have developed a compact laser optics system with a volume holographic grating (VHG) element for the SEOP system. We report the design of our spin filter system and some results of the He polarizing experiments in this paper.