Development and application of a He neutron spin filter at J-PARC

J-PARCにおけるHe中性子フィルターの開発とその利用

奥平 琢也; 奥 隆之   ; 猪野 隆*; 林田 洋寿*; 吉良 弘*; 酒井 健二 ; 廣井 孝介  ; 高橋 慎吾*; 相澤 一也  ; 遠藤 仁*; 遠藤 駿典   ; 日野 正裕*; 広田 克也*; 本田 孝志*; 池田 一貴*; 加倉井 和久*; 神原 理*; 北口 雅暁*; 小田 達郎*; 大下 英敏*; 大友 季哉*; 清水 裕彦*; 篠原 武尚   ; 鈴木 淳市*; 山本 知樹*

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; Endo, Shunsuke; Hino, Masahiro*; Hirota, Katsuya*; Honda, Takashi*; Ikeda, Kazutaka*; Kakurai, Kazuhisa*; Kambara, Wataru*; Kitaguchi, Masaaki*; Oda, Tatsuro*; Oshita, Hidetoshi*; Otomo, Toshiya*; Shimizu, Hirohiko*; Shinohara, Takenao; Suzuki, Junichi*; Yamamoto, Tomoki*

We are developing a neutron polarizer with polarized He gas, referred to as a He spin filter, based on the Spin Exchange Optical Pumping (SEOP) for polarized neutron scattering experiments at Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). A He gas-filling station was constructed at J-PARC, and several He cells with long spin relaxation times have been fabricated using the gas-filling station. A laboratory has been prepared in the MLF beam hall for polarizing He cells, and compact pumping systems with laser powers of 30 W and 110 W, which can be installed onto a neutron beamline, have been developed. A He polarization of 85% was achieved at a neutron beamline by using the pumping system with the 110 W laser. Recently, the first user experiment utilizing the He spin filter was conducted, and there have been several more since then. The development and utilization of He spin filters at MLF of J-PARC are reported.