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