Recent advancements of wide-angle polarization analysis with 3He neutron spin filters

6th European Conference on Neutron Scattering

Chen, W.C.^1,2 ; Gentile, T.R.^1 ; Ye, Q.^1,2 ; Kirchhoff, A.^1 ; Watson, S.M.^1 ; Rodriguez-Rivera, J.A.^1,2 ; Qiu, Y.^1 ; Broholm, C.^1,3

National Institute of Standards and Technology, Gaithersburg

MD

20899, United States^1

University of Maryland, College Park

MD

20742, United States^2

John Hopkins University, Baltimore

MD

21218, United States^3

关键词: 3 He polarization;    3He neutron spin filters;    Crystal spectrometer;    National Institute of Standards and Technology;    Neutron spin filters;    Polarization analysis;    Spin exchange optical pumping;    Stray magnetic fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/746/1/012016/pdf
DOI  :  10.1088/1742-6596/746/1/012016

来源: IOP

【 摘 要 】

Wide-angle polarization analysis with polarized3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over the past several years, the apparatus has undergone many upgrades to address the fundamental requirements for wide angle polarization analysis using spin exchange optical pumping based3He NSFs. In this paper, we report substantial improvements in the on-beam-line performance of the apparatus and progress toward routine user capability. We discuss new standard samples used for3He NSF characterization and the flipping ratio measurement on MACS. We further discuss the management of stray magnetic fields produced by operation of superconducting magnets on the MACS instrument, which can significantly reduce the3He polarization relaxation time. Finally, we present the results of recent development of horseshoe-shaped wide angle cells.