Highly polarized epithermal neutron beam using polarized 3He gas at J-PARC
Abstract
We have realized a highly polarized epithermal neutron beam using an in-situ polarized 3He spin filter at the high-intensity pulsed neutron facility J-PARC. A neutron polarization exceeding 80% was achieved for epithermal neutrons with energies below 1 eV, including a polarization of 86.4 ± 0.5% for 0.75 eV neutrons, which corresponds to the resonance energy of the p-wave compound state in the 139La+n system. The spin filter consisted of a 20-cm-long, 3.2-atm 3He gas cell polarized on the beamline using a compact laser-optics system for spin-exchange optical pumping (SEOP). A 3He polarization of approximately 78% was stably maintained on the beamline for more than 100 hours. The polarized epithermal neutron beam developed in this work provides a powerful tool for studies of discrete symmetry violations, including measurements of enhanced parity violation in neutron absorption by medium-heavy nuclei such as 139La and searches for time-reversal symmetry violation in neutron-nucleus systems.
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BibTeX
@misc{asai2026highly,
title = {{Highly polarized epithermal neutron beam using polarized 3He gas at J-PARC}},
author = {K. Asai and S. Endo and S. Hayashi and H. Isozaki and T. Ino and W. Kambara and S. Kawamura and A. Kimura and M. Kitaguchi and S. Kudo and R. Kobayashi and T. Oku and T. Okudaira and M. Okuizumi and H. M. Shimizu and K. Shimodaira and Y. Suto and S. Takada and S. Takahashi and H. Tanaka and Y. Tsuchikawa and T. Yamaguchi},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00106},
eprint = {2611.00106},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00106},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Highly polarized epithermal neutron beam using polarized 3He gas at J-PARC
AU - K. Asai
AU - S. Endo
AU - S. Hayashi
AU - H. Isozaki
AU - T. Ino
AU - W. Kambara
AU - S. Kawamura
AU - A. Kimura
AU - M. Kitaguchi
AU - S. Kudo
AU - R. Kobayashi
AU - T. Oku
AU - T. Okudaira
AU - M. Okuizumi
AU - H. M. Shimizu
AU - K. Shimodaira
AU - Y. Suto
AU - S. Takada
AU - S. Takahashi
AU - H. Tanaka
AU - Y. Tsuchikawa
AU - T. Yamaguchi
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00106
UR - https://arxiv.org/abs/2611.00106
AB - We have realized a highly polarized epithermal neutron beam using an in-situ polarized 3He spin filter at the high-intensity pulsed neutron facility J-PARC. A neutron polarization exceeding 80% was achieved for epithermal neutrons with energies below 1 eV, including a polarization of 86.4 ± 0.5% for 0.75 eV neutrons, which corresponds to the resonance energy of the p-wave compound state in the 139La+n system. The spin filter consisted of a 20-cm-long, 3.2-atm 3He gas cell polarized on the beamline using a compact laser-optics system for spin-exchange optical pumping (SEOP). A 3He polarization of approximately 78% was stably maintained on the beamline for more than 100 hours. The polarized epithermal neutron beam developed in this work provides a powerful tool for studies of discrete symmetry violations, including measurements of enhanced parity violation in neutron absorption by medium-heavy nuclei such as 139La and searches for time-reversal symmetry violation in neutron-nucleus systems.
ER -