Polarized eV neutrons can address interesting scientific questions in nuclear physics, particle physics, and astrophysics/cosmology. We present the first experiment to polarize the neutrons on the Back-n beamline at the Chinese Spallation Neutron Source (CSNS) using an in-situ NSF using spin-exchange optical pumping (SEOP) of 3He. A 3He polarization of 68%±0.7% for this in-situ NSF was measured through neutron transmission method at Back-n.This is high enough to enable new experiments on the Back-n beamline. Polarized neutron, Polarized nuclei, CSNS, White neutron, Fundamental physics research PACS number(s): 24.80.+y, 67.30.ep, 29.27.Hj , 24.70.+s , 32.10.Dk
@article{arxiv.2409.16598,
title = {First Use of a Polarized $^3$He Neutron Spin Filter on the Back-n White Neutron Source of CSNS},
author = {Mofan Zhang and Zhou Yang and Junpei Zhang and Chuyi Huang and Tianhao Wang and Yonghao Chen and Ruirui Fan and W. Michael Snow},
journal= {arXiv preprint arXiv:2409.16598},
year = {2025}
}