Research on concentrations and isotopic abundances of retractory siderophile elements in Ca, Al-rich inclusions and estimation of chemical and physical conditions of the primitive solar nebula

为了估计原始太阳星云的化学和物理条件，研究了Allende CV3球粒陨石中富含Ca、al的包裹体。开发了难熔亲铁元素的定量分析和同位素比值测定方法，并进行了绝灭核素的寻找。从国家科学博物馆收藏的3块Allende陨石标本中分离出3个富Ca、al的包裹体，包括一个lcm半径的球体，其中1个为粗粒包裹体，通过SEM-EDX观察，1个为含镁铝尖晶石的a型包裹体；另一个包裹体可能是C型，因为钙长石的丰度很高；使用广岛大学的SIMS，在C型包裹体的钙长石中观察到由于灭绝核素-26而导致的Mg-26过量。此外，在H球粒的酸溶部分中检测到痕量的灭绝核素-135。除了成熟的NAA方法外，还探索了使用ICP-MS定量分析难熔亲铁元素的方法。必须监测难熔亲铁元素的敏感性变化，并在测量Os时观察到严重的记忆效应。对于铂族元素和其他亲铁元素的负热电离质谱，与K CJ教授合作研究了在混合溶液中形成负热电离子的基本行为。使用Pt单灯丝法，从相同数量的元素中产生的负热离子强度为Re > Os > Ir—Ru > Mo。Re灯丝法可以用于更好地电离W和Mo。

In order to estimate chemical and physical conditions of the primitive solar nebula, Ca, Al-rich inclusions in the Allende CV3 chondrite were investigated. Methods for quantitative analysis and isotopic ratio measurement of refractory siderophile elements were developed and a search for extinct nuclides was performed.Three Ca, Al-rich inclusions including a lcm-radius spherule were separated from three specimens of the Allende meteorite in the collection of the, National Science Museum A11 of them are coarse-grained inclusions and, from observation using SEM-EDX, one is classified as a Type A inclusion with melilite and spinel ; another inclusion is probably a Type C because of high abundance of anorthite ; the other could be a Type B Using a SIMS at Hiroshima University, Mg-26 excesses due to the extinct nuclideAl-26 were observed in anorthite of the Type C inclusion Also, a trace of the extinct nuclide Cs-135 was detected in an acid-soluble fraction in an H chondriteMethods for quantitative analysis of refractory siderophile elements using an ICP-MS were explored in addition to the well-developed NAA methods. Change of sensitivities of the refractory siderophile elements had to be monitored and severe memory, effects were observed at the measurements of Os. For the negative thermal ionization mass spectrometry of the platinum group elements and other siderophile elements, basic behaviors of formation of negative thermal ions from a mixed solution were investigated in collaboration with Prof. K CJ. Heumann at the University of Mainz Using a Pt single filament method, the intensities of negative thermal ions from the same amount of elements were Re > Os > Ir -- Ru > Mo The Re filament method could be used for better ionization of W and Mo.