Current status of a He spin filter development

Oku, Takayuki   ; Sakai, Kenji ; Hiroi, Kosuke  ; Watanabe, Masao  ; Shinohara, Takenao   ; Aizawa, Kazuya  ; Kakurai, Kazuhisa*; Kira, Hiroshi*; Hayashida, Hirotoshi*; Kiriyama, Koji*; Suzuki, Junichi*; Ino, Takashi*; Okawara, Manabu*; Noda, Yohei*; Oyama, Kenji*; Okudaira, Takuya*; Okada, Anju*; Kitaguchi, Masaaki*; Shimizu, Hirohiko*; Lee, W. T.*; Tong, T. X.*

We have been developing a He neutron spin filter for application at J-PARC MLF. The He neutron spin filter is available for neutrons in a wide energy range, and is also effective for a divergent neutron beam. Therefore, it is very useful in the neutron scattering experiment. So far, we have developed a compact laser optics with a volume holographic grating (VHG) elements, and have constructed an on-beam SEOP based He neutron spin filter. The polarization analysis tests were performed with the He neutron spin filter at several neutron beamlines for the sans, reflectivity and neutron imaging experiments. To extend the application range of the He neutron spin filter at J-PARC MLF, we plan to develop larger size cells, higher power laser for the SEOP, and prepare working area for the filter inside the MLF experimental hall.