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Sensitive neutron transverse polarization analysis using a 3He spin fi lter



Y.- Y. Jau, Wangchun Chen, Thomas R. Gentile, Daniel S. Hussey


We report an experimental implementation for neutron transverse polarization analysis that is able to detect a small angular change (10^-3 rad) of neutron spin orientation and works for both monochromatic and polychromatic neutron beams. Our approach employs a 3He spin fi lter inside a solenoid with an analyzing direction perpendicular to the incident neutron polarization direction. The method was tested with polarized neutron beams and a spin rotator placed inside a mu-metal shield just upstream of the analyzer. No cryogenic superconducting shields or additional neutron spin manipulations are needed. With a counting detector, we experimentally show that the angular resolution delta-theta( = 1/Pn A sqrt(N))rad is only determined by the counting statistics for the total counts N, and the product of the neutron polarization Pn and the analyzing power A. With a high-flux neutron beam, 10^-6 rad angular sensitivity is feasible within a day. This simple, classical-quantum-limited transverse polarization analysis scheme may reduce the overall complexity of experimental implementation for applications requiring sensitive neutron polarimetry and improve the precision in fundamental science studies and polarized neutron imaging.
Review of Scientific Instruments


3He, imaging, neutron, polarization, spin filter
Created July 8, 2020, Updated July 10, 2020