| Project/Area Number |
10440076
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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 |
素粒子・核・宇宙線
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
GONO Yasuyuki Kyushu University, Faculty of Sciences, Professor, 大学院・理学研究院, 教授 (50016127)
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| Co-Investigator(Kenkyū-buntansha) |
KIKEGAWA Takumi High Energy Accelerator Research Organization, Institute of Materials Structure Science, Research Associate, 物質構造科学研究所, 助手 (70195220)
KATANO Rintaro Kyoto University, The Institute for Chemical Research, Research Associate, 化学研究所, 助手 (50231254)
ISOZUMI Yasuhito Kyoto University, Radioisotope Research center, Professor, RI総合研究センター, 教授 (50027603)
KAJINO Toshitake National Astronomical Observatory, Associate Professor, 理論天文学研究系, 助教授 (20169444)
ODAHARA Atsuko Nishinippon Institute of Technology, Department of Engineering, Associate Professor, 工学部, 助教授 (30264013)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥11,700,000 (Direct Cost: ¥11,700,000)
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| Keywords | High pressure / Nuclear Physics / Physics under an extreme condition / Change of a nuclear decay constant / 超高圧下の原子核崩壊定数 / ^<99m>Tcのガンマー線測定 / ガンマー線強度の差の時間変化 |
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| Research Abstract |
The experiments on a change of decay constant were made in the past 3 years as follows ; Site of the experiments : The RI research center of Kyoto University annex. Members : Y.Gono, Y.Isozumi, R.Katano, T.Kikegawa, A.Odahara, T.Kajino (With great helps by Mr. K.Saito and T.Tsutsumi : graduate students of Kyushu University)
1st year (1998) ; Meeting to discuss when and how proceed this project. Then we started to buy necessary equipments using the grant given by JSPS.
2nd year (1991) ; Blank test was made, i.g.a test of RI-source preparation and a measurement of a gamma-ray spectrum.
3rd year (2000) ; Aull experiments was were made once with an ultra high-pressure (21 GPa).
Results were analysed by using a differential method. However the result was Δλ/λ = (2.1 ±2.1) x 10^<-4> which was not consistent with previously reported ones. Then a run was made by using 2 sources both under normal pressures. The result was an enough accuracy to compare the results with those of the past. In the 1st
… More
run there were problems of back-grounds. Since we made experiments using two sources and one detector, we measured γ-ray spectra by moving lead shields located between sources and the detector. Then the background changed depending on the lead positions. Also a background changed depending on time in the first run though these problems were solved in the second run.
We conclude that the experimental accuracy is enough to observe the previously reported Δλ/λ if all the conditions are reproduced when an ultra high-pressure is applied to one source. So we decided to continue this project even without a further financial support.
The experiments on a change of decay constant were made in the past 3 years as follows ; Site of the experiments : The RI research center of Kyoto University annex.
Members : Y.Gono, Y.Isozumi, R.Katano, T.Kikegawa, A.Odahara, T.Kajino (With great helps by Mr. K.Saito and T.Tsutsumi : graduate students of Kyushu University) 1st year (1998) ; Meeting to discuss when and how proceed this project. Then we started to buy necessary equipments using the grant given by JSPS.
2nd year (1991) ; Blank test was made, i.g.a test of RI-source preparation and a measurement of a gamma-ray spectrum.
3rd year (2000) ; Aull experiments was were made once with an ultra high-pressure (21 GPa).
Results were analysed by using a differential method. However the result was Δλ/λ = (2.1 ±2.1) x 10^<-4> which was not consistent with previously reported ones. Then a run was made by using 2 sources both under normal pressures. The result was an enough accuracy to compare the results with those of the past. In the 1st run there were problems of back-grounds. Since we made experiments using two sources and one detector, we measured λ-ray spectra by moving lead shields located between sources and the detector. Then the background changed depending on the lead positions. Also a background changed depending on time in the first run though these problems were solved in the second run.
We conclude that the experimental accuracy is enough to observe the previously reported Δλ/λ if all the conditions are reproduced when an ultra high-pressure is applied to one source. So we decided to continue this project even without a further financial support. Less
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