3He spin filter based polarized neutron capability at the NIST Center for Neutron Research

International Workshop on Neutron Optics and Detectors

Chen, W.C.^1,2 ; Gentile, T.R.^1 ; Erwin, R.^1 ; Watson, S.^1 ; Ye, Q.^1,2 ; Krycka, K.L.^1 ; Maranville, B.B.^1

National Institute of Standards and Technology, Gaithersburg, MD 20899, United States^1

University of Maryland, College Park, MD 20742, United States^2

关键词: 3He neutron spin filters;    National Institute of Standards and Technology;    Nuclear Magnetic Resonance (NMR);    Polarization analysis;    Polarized neutron instrumentation;    Polarized neutron scattering;    Spin exchange optical pumping;    Triple axis spectrometers;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/528/1/012014/pdf
DOI  :  10.1088/1742-6596/528/1/012014

来源: IOP

【 摘 要 】

A3He neutron spin filter (NSF) program for polarized neutron scattering was launched in 2006 as part of the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) Expansion Initiative. The goal of the project was to enhance the NCNR polarized neutron measurement capabilities. Benefitting from more than a decades development of spin-exchange optical pumping (SEOP) at NIST, we planned to employ SEOP based3He neutron spin filters for the polarized neutron scattering community. These3He NSF devices were planned for use on different classes of polarized neutron instrumentation at the NCNR, including triple-axis spectrometers (TAS), small-angle neutron scattering instruments (SANS), reflectometers, and wide-angle polarization analysis. Among them, the BT-7 thermal TAS, NG-3 SANS, and MAGIK reflectometer have already been in the user program for routine polarized beam experiments. Wide-angle polarization analysis on Multi-Axis Crystal Spectrometer (MACS) has been developed for user experiments. We describe briefly the SEOP systems dedicated for polarized beam experiments and polarizing neutron development for each instrument class. We summarize the current status and polarized neutronic performance for each instrument. We present a3He NSF hardware and software interface to allow for synchronization of3He polarization inversion (neutron spin flipping) and free-induction decay (FID) nuclear magnetic resonance (NMR) measurements with neutron data collection.