2022 Fiscal Year Final Research Report

Elucidation of nucleosynthesis scenario by establishing a new isochronism tuning method

Research Project

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Project/Area Number	19K14751
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
Research Institution	Japan Atomic Energy Agency
Principal Investigator	Suzaki Fumi 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門原子力科学研究所先端基礎研究センター, 研究職 (70779727)
Project Period (FY)	2019-04-01 – 2023-03-31
Keywords	イオン蓄積リング
Outline of Final Research Achievements	Rare-RI Ring is a storage ring for precise mass measurement of unstable nuclei to elucidate the r-process. For accurate mass measurement, it is necessary to establish a state of isochronism, in which particles circulating the ring have the same period regardless of their momentum, with a high degree of accuracy. This study aims to establish a new isochronism tuning method that can be used at high vacuum, which is necessary for the mass measurement of more unstable nuclei, and to guarantee the accuracy of the mass measurement. Although the new isochronism tuning method combining a RF cavity and the existing resonant Schottky pick-up was not tested in beam experiments during the entire research period, analysis of data obtained from Rare-RI Ring experiments with the resonant Schottky pick-up isochronism tuning provided insight into the realization of the new method.
Free Research Field	原子核物理学
Academic Significance and Societal Importance of the Research Achievements	鉄より重い元素がどのようにできたのか、という疑問に答える仮説として、原子核が一気に中性子を吸収して崩壊し原子番号を増やして進むRプロセスがある。Rプロセス解明のため経路上核の質量精密測定を行う稀少RIリングが理化学研究所に建設された。研究成果である稀少RIリング実験における共鳴ショットキーピックアップの等時性調整手法の実現とデータ解析により、RFキャビティの設計や現手法への課題等の知見を得た。本研究により得た知見は高い真空度でも適用可能な新しい等時性調整手法の確立に活用できるため、将来稀少RIリングで実施するより不安定な核の質量精密測定の実現とRプロセス解明に大きな進展をもたらす。