| Project/Area Number |
19K03899
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
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| Research Institution | High Energy Accelerator Research Organization |
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Principal Investigator |
Schury Peter 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 (30462724)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2021: ¥130,000 (Direct Cost: ¥100,000、Indirect Cost: ¥30,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
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| Keywords | ion source / Ion source / Refractory elements / Photoionization / Atomic mass / Photo-ionization / Deep UV LED / イオン源 / 質量測定 / LED |
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| Outline of Research at the Start |
Successful development of this deep-UV LED-based ionization cell will allow for simple and clean production of appropriate reference ions for mass measurements of r-process nuclei produced in multinucleon transfer reactions. This will allow for accurate, high-precision, direct mass determinations of neutron-rich isotopes of elements from Ta through Pt reaching to the N=126 shell closure. Such mass measurements are vitally necessary for a deeper understanding of the synthesis of the heaviest elements via the r-process.
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| Outline of Final Research Achievements |
In order to understand the origins of the heaviest elements -- thorium and uranium for instance -- in the universe, it is necessary to precisely know the energies that bind nuclei of heavy isotopes of elements near platinum. To make such measurements with high accuracy requires use of reference ions with nearly the same mass-to-charge ratio as those under study, otherwise mass-dependent anomalies can cause systematic errors in the measurement. The aforementioned nuclei typically have a mass of A~200 atomic units and are delivered to our spectrometer with a charge of q=2, resulting in a mass-to-charge ratio of A/q~100. However, our standard offline reference ions have A/q=87 and A/q=133, both of which are rather far from the species of interest. So, we have attempted to produce a simple offline ion source of stable platinum group elements -- Pt, W, Re, and Ir -- by using ultraviolet light emitting diodes to excite and remove one electron from the atoms.
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| Academic Significance and Societal Importance of the Research Achievements |
The ability to more accurately measure the masses of exotic nuclides will lead towards answering two major outstanding questions: how were the heaviest elements (thorium and uranium) created in the universe and do natural mechanisms allow for the production of superheavy elements?
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