Precise life-time measurements of unstable nuclides in capsulated in fullerene cage

精确测量富勒烯笼中封装的不稳定核素的寿命

• 批准号: 12640532
• 负责人: OHTSUKI Tsutomu
• 金额: $ 2.24万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640532/
• 关键词: FULLERENE; DECAY CONSTANT; Be-7; 半減期; 原子核反跳

A precise measurement of decay constant for ^7Be encapsulated in fullerene cage were performed with extreme conditions, such as 6K temperature. The results measured in 6K were compared with data for the normal temperature and that presented so far in the different chemical forms.^7Be atom can penetrate into the C_<60> to produce ^7Be@C_<60> by a recoil process of the nuclear reactions, ^<12>C(γ , α n)^7Be or ^7Li(p,n)^7Be. Radioactive endohedral fullerenes produced by the nuclear recoil, namely ^7B@C_<60>, were detected using radiochemical and radiochromatographic techniques in the final solution. To measure the decay constant of ^7Be encapsulated in the cage, ^7B@C_<60>, the same apparatus in a system (Ge-detector, MCA, Computer, etc.) was used. Furthermore, an automated sample-exchange system were installed in this term for the reduction of systematical errors. Data were collected at 8 hours intervals in the MCA system. Analysis was performed using by a least-squares fitting with the CERN program, PAW. Finally we obtained the life-time of 52.98±0.05 day for 6K and 51.97±0.05 for normal temperature, respectively. It seems that a relatively large change was obtained compared to the value resented so far.

在极端条件下，如6K温度下，对富勒烯笼中的^7Be衰变常数进行了精确测量。在6K下测量的结果与常温下的数据以及迄今为止以不同化学形式呈现的数据进行了比较。7Be原子可以通过核反应的反冲过程进入C_<60>，生成^7Be@C_<60>，即^<12>C（γ，α n）^7Be或^7Li（p，n）^7Be。利用放射化学和放射色谱技术在最终溶液中检测到由核反冲产生的放射性内嵌富勒烯，即^7B@C_<60>。为了测量笼中的^7Be的衰变常数<60>，在一个系统（Ge探测器，MCA，计算机等）中使用了相同的装置。用了此外，为了减少系统误差，本学期还安装了自动样品交换系统。在MCA系统中以8小时间隔收集数据。使用CERN程序PAW通过最小二乘拟合进行分析。最后得到6K和常温下的寿命分别为52.98±0.05天和51.97±0.05天。与迄今为止所抱怨的价值相比，似乎获得了相对较大的变化。

项目成果

K.Shiga et al.: "Formation of N-doped C_<60> studied by ab initio molecular dynamics simulation"Material Transitions. 42. 2189-2193 (2001)

K.Shiga 等人：“通过从头算分子动力学模拟研究 N 掺杂 C_<60> 的形成”材料转变。

T.Ohtsuki et al.: "Se-atom incorporation in fullerene by using nuclear recoil and ab initio MD simulations"Physical Review B. 65. 0734021-0734024 (2002)

T.Ohtsuki 等人：“Se-atom incorporation in fullerene by using Nuclear recoil and ab initio MD models”Physical Review B. 65. 0734021-0734024 (2002)

S.Ilievski et al.: "Multi-photon giant resonances and coulomb Assion of ^<238>V"Nuclear Physics. A687. 178-183 (2001)

S.Ilievski 等人：“多光子巨共振和^<238>V 的库仑Assion”核物理。

T. Ohtsuki et al.: "Systematic study of foreign-atom-doped fullerenes by using nuclear recoil method and their MD simulation"J. Chemical Physics. 112. 2834-2842 (2000)

T. Ohtsuki等：“利用核反冲法系统研究外源原子掺杂富勒烯及其MD模拟”J.

K. Shiga et al.: "Formation of N-doped C60 studied by ab initio molecular dynamics simulations"Materials Transitions. 42. 2189-2193 (2001)

K. Shiga 等人：“通过从头算分子动力学模拟研究 N 掺杂 C60 的形成”材料转变。