Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

International Conference on Polarised Neutrons for Condensed Matter Investigations 2014

Hayashida, H.^1 ; Oku, T.^2 ; Kira, H.^1 ; Sakai, K.^2 ; Hiroi, K.^2 ; Ino, T.^3 ; Shinohara, T.^2 ; Imagawa, T.^4 ; Ohkawara, M.^5 ; Ohoyama, K.^5 ; Kakurai, K.^6 ; Takeda, M.^2,6 ; Yamazaki, D.^2 ; Oikawa, K.^2 ; Harada, M.^2 ; Miyata, N.^1 ; Akutsu, K.^1 ; Mizusawa, M.^1 ; Parker, J.D.^1 ; Matsumoto, Y.^1 ; Zhang, S.^1 ; Suzuki, J.^1 ; Soyama, K.^2 ; Aizawa, K.^2 ; Arai, M.^2

Comprehensive Research Organization for Science and Society, Ibaraki-Tokai

319-1106, Japan^1

J-PARC Center, Japan Atomic Energy Agency, Ibaraki-Tokai

319-1195, Japan^2

High Energy Accelerator Research Organization (KEK), Ibaraki, Tsukuba

305-0801, Japan^3

Central Research Laboratory, Hitachi Ltd., 1-1, Omika-cho 7, Hitachi, Ibaraki

319-1292, Japan^4

Institute for Materials Research, Tohoku University, Miyagi, Sendai

980-8577, Japan^5

Quantum Beam Science Center, Japan Atomic Energy Agency, Ibaraki-Tokai

319-1195, Japan^6

关键词: 3 He polarization;    3He neutron spin filters;    Circularly polarized lasers;    Magnetic imaging;    Magnetic steel sheets;    Nuclear magnetic resonance techniques;    Polarized neutrons;    Spin exchange optical pumping;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/711/1/012007/pdf
DOI  :  10.1088/1742-6596/711/1/012007

来源: IOP

【 摘 要 】

We have been developing a3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the3He NSF can work as a π-flipper for a polarized neutron beam by flipping the3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The3He polarization reached 70% and was stable over one week. A demonstration of the3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.