2013 Fiscal Year Final Research Report
Electromagnetic nuclear moments around neutron magic number 20 and 28
| Project/Area Number |
22340071
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | The Institute of Physical and Chemical Research |
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Principal Investigator |
UENO Hideki 独立行政法人理化学研究所, 仁科加速器研究センター, 主任研究員 (50281118)
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| Co-Investigator(Kenkyū-buntansha) |
ASAHI Koichiro 東京工業大学, 大学院・理工学研究科(理学系), 教授 (80114354)
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| Co-Investigator(Renkei-kenkyūsha) |
ICHIKAWA Yuichi 独立行政法人理化学研究所, 仁科加速器研究センター, 研究員 (20532089)
YOSHIMI Akihiro 独立行政法人理化学研究所, 仁科加速器研究センター, 客員研究員 (40333314)
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| Project Period (FY) |
2010-04-01 – 2014-03-31
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| Keywords | 核電磁モーメント / 核スピン偏極 / β-NMR法 / γ線摂動角分布法 / 殻構造 / RIビーム / 魔法数 / 中性子過剰核 |
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| Research Abstract |
The purpose of this study is to investigate the structure of far neutron-rich nuclei around neutron magic number N = 20 and 28 through the measurement of electromagnetic nuclear moments. In the nuclear region of N = 20, a ground-state electric quadrupole (Q) moment of 33Al was measured at GANIL, France. The obtained Q shows a large outward discrepancy from a single particle value and shell model calculations within the conventional sd model space, suggesting the erosion of N = 20 shell closure. For the N = 28 region, the Q moment of the isomeric state of 43S at 320 keV was measured at the RIKEN RIBF facility. The data shows that the 43S deformation is modest in spite of the level inversion, suggesting a strong deformation of the ground state and a shape coexistence in the low-lying states. In this study, a noble method to produce spin-aligned RI beams utilizing two-step fragmentation reaction combined with momentum dispersion-matching of the ion optics technique has been developed.
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