Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Neutron Polarimetry Using a Polarized 3He Cell for the aCORN Experiment



Benjamin C. Schafer, W A. Byron, Wangchun Chen, B Collett, Maynard S. Dewey, Thomas R. Gentile, Md. T. Hassan, Gordon L. Jones, Alexander Komives, Fred E. Wietfeldt


The neutron polarization of the NG-C beamline at the NIST Center for Neutron Research was measured as part of the aCORN neutron beta decay experiment. Neutron transmission through a polarized 3He spin filter cell was recorded while adiabatic fast passage (AFP) nuclear magnetic resonance (NMR) reversed the polarization direction of the 3He in an eight-step sequence to account for drifts. The dependence of the neutron transmission on the spin filter direction was used to calculate the neutron polarization. The time dependent transmission was fit to a model which included the neutron spectrum, and 3He polarization losses from spin relaxation and AFP-NMR. The neutron polarization averaged over the spectrum of the NG-C beam was found to be ∣n∣ ≤ 4 × 10−4 with 90% confidence.
Nuclear Instruments & Methods in Physics Research A


Neutrons, Polarimetry, 3He cell, Spin filter


Schafer, B. , Byron, W. , Chen, W. , Collett, B. , Dewey, M. , Gentile, T. , Hassan, M. , Jones, G. , Komives, A. and Wietfeldt, F. (2020), Neutron Polarimetry Using a Polarized 3He Cell for the aCORN Experiment, Nuclear Instruments & Methods in Physics Research A, [online],, (Accessed May 27, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created November 16, 2020, Updated October 12, 2021