2016 Fiscal Year Final Research Report

Beta-decay spectroscopy of waiting-point nuclei in the third peak of element abundance pattern produced by r-process

Research Project

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Project/Area Number	26247044
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Research Field	Particle/Nuclear/Cosmic ray/Astro physics
Research Institution	High Energy Accelerator Research Organization
Principal Investigator	Jeong SunChan 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 客員教授 (00262105)
Co-Investigator(Kenkyū-buntansha)	平山賀一大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 研究機関講師 (30391733) 宮武宇也大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (50190799) 石山博恒大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 研究機関講師 (50321534) 渡邉裕大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 研究機関講師 (50353363)
Research Collaborator	WADA Michiharu SONODA Tetsu KIMURA Souta MUKAI Momo Kim Y. H. Huyse M. Kudryavtsev Yu. Duppen P. Van
Project Period (FY)	2014-06-27 – 2017-03-31
Keywords	国際情報交換 / ベルギー / 元素合成 / アルゴンガスセル / レーザー共鳴イオン化
Outline of Final Research Achievements	In order to reveal the astrophysical environment for the formation of the 3rd peak in the solar r-abundance pattern produced by the r-process, we performed precise beta-decay spectroscopy of the nuclei around neutron magic number N=126. We developed the following three items to proceed with our research. (1) We developed a doughnut-shaped gas-cell and could increase the production yield by a factor of ten. (2)We installed a new dye laser and established laser resonance ionization schemes of the heavy elements with atomic number Z=73-78. (3)We developed highly efficient and low-background gas-counter for the lifetime measurement by detecting the beta-rays. As the result, we can successfully measure the lifetimes of 199,201Pt, 196,197,198,201Ir and 196Os. Moreover, we can evaluate the magnetic dipole moments and the change of the charge radii by using the in-gas-cell laser ionization spectroscopy technique successfully.
Free Research Field	実験核物理