Measurement of the neutron beam polarization of BL05/NOP beamline at J-PARC

• Published in: Physica. B, Condensed matter Vol. 406; no. 12; pp. 2424 - 2428
• Main Authors: Ino, T., Arimoto, Y., Yoshioka, T., Mishima, K., Taketani, K., Muto, S., Shimizu, H.M., Kira, H., Sakaguchi, Y., Oku, T., Sakai, K., Shinohara, T., Suzuki, J., Otono, H., Oide, H., Yamashita, S., Imajo, S., Funahashi, H., Yamada, M., Iwashita, Y., Kitaguchi, M., Hino, M., Suzuki, Z., Sanuki, T., Seki, T., Hirota, K., Ikeda, K., Sato, H., Otake, Y., Ohmori, H., Morishima, T., Shima, T.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier B.V 01.06.2011; Elsevier
• Subjects: 3He polarization; Asymmetry; Atom and neutron optics; Beta decay; Classical and quantum physics: mechanics and fields; Condensed matter; Exact sciences and technology; J-PARC; Matter waves; Neutron beams; Neutron beta decay; Neutron sources; Neutron spin filter; Physics; Polarimetry; Polarization; Polarized neutron; Spallation; Spin-exchange optical pumping; Spin-exchange optical pumping; Polarized neutron; J-PARC; 3He polarization; Neutron spin filter; Neutron beta decay; Data analysis; Data acquisition systems; Instrumentation; Optical pumping; Errors; Asymmetry; J-PAR; Spin exchange; Neutron beams; He polarization; Polarimetry; Spin filter
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2011.01.009

We measured the neutron beam polarization of the BL05/NOP (Neutron Optics and Physics) beamline at J-PARC with an accuracy of less than 10−3 using polarized 3He gas as a neutron spin analyzer. Precise polarimetry of the neutron beam is necessary to understand the beamline optics as well as for the asymmetry measurements of the neutron beta decay, which are planned in this beamline. ► We have measured neutron beam polarization with an accuracy of 0.03% using a 3He neutron spin filter. ► This accuracy was achieved by flipping the 3He polarization with adiabatic fast-passage (AFP) NMR. ► The 3He spin flipping canceled most of systematic uncertainties. ► Such accuracy is necessary for the precise neutron beta decay measurements planned at BL05 of the J-PARC spallation neutron source.