Abstract

To solve the “neutron lifetime puzzle,” where measured neutron lifetimes differ depending on the measurement methods, an experiment with a pulsed neutron beam at J-PARC is in progress. In this experiment, neutrons are bunched into 40-cm lengths using a spin flip chopper (SFC), where the statistical sensitivity was limited by the aperture size of the SFC. The SFC comprises three sets of magnetic supermirrors and two resonant spin flippers. In this paper, we discuss an upgrade to enlarge the apertures of the SFC. With this upgrade, the statistics per unit time of the neutron lifetime experiment increased by a factor of 2.8, while maintaining a signal-to-noise ratio of 250–400, which is comparable to the previous one. Consequently, the time required to reach a precision of 1 s in the neutron lifetime experiment was reduced from 590 to 170 days, which is a significant reduction in time. This improvement in the statistics will also contribute to the reduction of systematic uncertainties, such as background evaluation, fostering further advancements in the neutron lifetime experiments at J-PARC.

Details

Title
Performance of the Fully Equipped Spin Flip Chopper for the Neutron Lifetime Experiment at J-PARC
Author
Mishima, K 1   VIAFID ORCID Logo  ; Ichikawa, G 1   VIAFID ORCID Logo  ; Fuwa, Y 2   VIAFID ORCID Logo  ; Hasegawa, T 3 ; Hino, M 4   VIAFID ORCID Logo  ; Hosokawa, R 5   VIAFID ORCID Logo  ; Ino, T 1   VIAFID ORCID Logo  ; Iwashita, Y 4   VIAFID ORCID Logo  ; Kitaguchi, M 1   VIAFID ORCID Logo  ; Matsuzaki, S 6 ; Mogi, T 7   VIAFID ORCID Logo  ; Okabe, H 3 ; Oku, T 8   VIAFID ORCID Logo  ; Okudaira, T 8   VIAFID ORCID Logo  ; Seki, Y 9   VIAFID ORCID Logo  ; Shimizu, H E 10   VIAFID ORCID Logo  ; Shimizu, H M 3   VIAFID ORCID Logo  ; Takahashi, S 8   VIAFID ORCID Logo  ; Tanida, M 6   VIAFID ORCID Logo  ; Yamashita, S 11   VIAFID ORCID Logo  ; Yokohashi, M 3 ; Yoshioka, T 5   VIAFID ORCID Logo 

1  Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) , 203-1, Shirakata, Tokai 319-1106 , Japan 
2  Japan Atomic Energy Agency , 2-4, Shikarata, Tokai 319-1195 , Japan 
3  Department of Physics, Nagoya University , Furocho, Chikusa, Nagoya 464-8602 , Japan 
4  Institute for Integrated Radiation and Nuclear Science, Kyoto University , 2, Asashiro-Nishi, Kumatori, Sennan-gun, Osaka 590-0494 , Japan 
5  Research Center for Advanced Particle Physics (RCAPP), Kyushu University , 744 Motooka Nishi-ku, Fukuoka 819-0395 , Japan 
6  Department of Physics, Kyushu University , 744 Motooka Nishi-ku, Fukuoka 819-0395 , Japan 
7  Department of Physics, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 , Japan 
8  J-PARC Center , 2-4, Shikarata, Tokai 319-1195 , Japan 
9  Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , 2-1-1, Katahira, Sendai 980-8577 , Japan 
10  Materials Structure Science Program, Graduate University for Advanced Studies, SOKENDAI, Shonan Village , Hayama 240-0193 , Japan 
11  Research and Regional Cooperation Office, Iwate Prefectural University , 152-52 Sugo, Takizawa, Takizawa 020-0693 , Japan 
Publication year
2024
Publication date
Sep 2024
Publisher
Oxford University Press
e-ISSN
20503911
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1093/ptep/ptae123
ProQuest document ID
3171501367
Copyright
© The Author(s) 2024. Published by Oxford University Press on behalf of the Physical Society of Japan. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.