Change of nuclear decay constant under ultra high-pressure

超高压下核衰变常数的变化

• 批准号: 10440076
• 负责人: GONO Yasuyuki
• 金额: $ 8.32万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10440076/
• 关键词: 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

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

在过去的3年中，对衰变常数的变化进行了如下实验：实验地点：京都大学附属研究中心。成员：Y.Gono，Y.Isozumi，R.卡塔诺，T.Kikegawa，A.Odahara，T.Kajino（在K.Saito先生和T.Tsutsumi先生的大力帮助下：九州大学研究生）第一年（1998年）;会议讨论何时以及如何进行该项目。第二年（1991年）进行了空白实验，即放射性同位素源的制备和γ射线谱的测量。第三年（2000年）在超高压（21 GPa）下进行了一次全实验，用微分法对实验结果进行了分析。但结果为Δλ/λ =（2.1 ±2.1）× 10 ~（-1）<-4>，与文献报道的结果不一致。然后通过使用两个源在正常压力下进行运行。结果是一个足够的准确性，以比较的结果与过去的。第1 ...更多信息 有背景的问题。由于我们使用两个源和一个探测器进行实验，我们通过移动位于源和探测器之间的铅屏蔽来测量γ射线谱。然后，背景根据铅的位置而变化。在第一次实验中，本底随时间变化，但第二次实验中这些问题得到了解决。我们的结论是，当超高压作用于一个源时，如果所有条件都能重现，实验精度足以观察到先前报道的Δλ/λ。因此，即使没有进一步的财政支持，我们也决定继续这个项目。在过去3年中进行了衰变常数变化的实验，具体如下;实验地点：京都大学附楼RI研究中心。成员：Y.Gono、Y.Isozumi、R.卡塔诺、T.Kikegawa、A.Odahara、T.Kajino（九州大学研究生齐藤光先生、堤田先生的大力协助下）第一年（1998年）;讨论何时以及如何进行该项目的会议。第二年（1991年）进行了空白实验，即放射性同位素源的制备和γ射线谱的测量。第三年（2000年）在超高压（21 GPa）下进行了一次全实验，用微分法对实验结果进行了分析。但结果为Δλ/λ =（2.1 ±2.1）× 10 ~（-1）<-4>，与文献报道的结果不一致。然后通过使用两个源在正常压力下进行运行。结果是一个足够的准确性，以比较的结果与过去的。在第一轮比赛中，出现了背景问题。由于我们使用两个源和一个探测器进行实验，我们通过移动位于源和探测器之间的铅屏蔽来测量λ射线光谱。然后，背景根据铅的位置而变化。在第一次实验中，本底随时间变化，但第二次实验中这些问题得到了解决。我们的结论是，当超高压作用于一个源时，如果所有条件都能重现，实验精度足以观察到先前报道的Δλ/λ。因此，我们决定继续这个项目，即使没有进一步的财政支持。少

项目成果

A.Odahara: "Study of Nuclear Decay Constant under Ultra High-Pressure"The 4th Korea-Japan Joint Symp. on Cyclotron Nuclear Spectroscou, Korean Cancer Center Hospital 1999.. (1999)

A.Odahara：“超高压下核衰变常数的研究”第四届韩日联合研讨会。

T.Tsutsumi: "Change of Nuclear Decay Constant under Ultra High-Pressure"54th Annural Meeting of JPS, Hiroshima University, 2000 Nuclear Spectroscopy. 28・. 3-12 (2000)

T. Tsutsumi：“超高压下核衰变常数的变化”第54届JPS年会，广岛大学，2000年核光谱学28・3-12（2000）。

K.Saito, Y.Gono, A.Odahara: "Dead Time Correction in γ-Ray Measurement with Rapidly Changing Counting Rate"The 105th Regional Meeting of JPS Kyushu Branch, Nagasaki. (1999)

K.Saito、Y.Gono、A.Odahara：“计数率快速变化的 γ 射线测量中的死区时间校正”JPS 九州分会第 105 届区域会议，长崎（1999 年）。

K.Saito: "Dead Time Correction in γ-Ray Measurement with Rapidly Changing Counting Rate"The 15th Regional Meeting of JPS Kyushu Branch, Nagasaki, 1999. (1999)

K.Saito：“快速改变计数率的 γ 射线测量中的死区时间校正”JPS 九州分会第 15 届区域会议，长崎，1999 年。（1999 年）

T.Tsutsumi, Y.Gono, A.Odahara, Y.Isozumi, R.Katano, T.Kikegawa, T.Suda, T.Kajino: "Change of Nuclear Decay Constant under Ultra High-Pressure 54th Annual Meeting of JPS, Hiroshima University, 2000"Nuclear Spectroscopy. 28. YJ3-12 (2000)

T.Tsutsumi、Y.Gono、A.Odahara、Y.Isozumi、R.Katano、T.Kikekawa、T.Suda、T.Kajino：“超高压下核衰变常数的变化第 54 届广岛 JPS 年会