New project for precise neutron lifetime measurement at J-PARC
| Autor: | Hideaki Uehara, Tamaki Yoshioka, Yoshihisa Iwashita, Takashi Ino, Hirochika Sumino, Daiichiro Sekiba, T. Tomita, Kaoru Taketani, Hideyuki Oide, Hirohiko M. Shimizu, Yusuke Nakano, Satoru Yamashita, Yoshichika Seki, Naoki Nagakura, Hidetoshi Otono, Jun Koga, Naoyuki Sumi, Takahito Yamada, Katsuya Hirota, Masaaki Kitaguchi, M. Yokohashi, Ryunosuke Kitahara, A. Morishita, S. Ieki, Hiroki Okabe, Tatsushi Shima, Kenji Mishima |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
Time projection chamber 010308 nuclear & particles physics QC1-999 Particle accelerator Neutron radiation 01 natural sciences law.invention Nuclear physics Chopper Big Bang nucleosynthesis law 0103 physical sciences Physics::Accelerator Physics Neutron J-PARC 010306 general physics Beam (structure) |
| Zdroj: | EPJ Web of Conferences, Vol 219, p 03003 (2019) |
| Popis: | The decay lifetime of free neutrons (∼880 s) is an important parameter of the weak interaction and for Big Bang Nucleosynthesis. However, results of measurements currently show discrepancies depending on the method used. As most experiments nowadays employ ultra cold neutrons, we have developed a new cold-beam experiment which we perform at the Japan Proton Accelerator Research Complex. As a special feature, a polarized neutron beam is bunched by a spin flip chopper. A time projection chamber operated with He and CO2gas, including a well-controlled amount of3He, is used for detection of the beta-decays and simultaneous determination of the beam intensity. Using the data between 2014 and 2016, we evaluated our first, preliminary result of the neutron lifetime as 896 ± 10(stat.)−10+14(sys.) s. We plan several upgrades to achieve our precision goal of 1 s. |
| Databáze: | OpenAIRE |
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