Science. 1965 Apr 30;148(3670):629-32. doi: 10.1126/science.148.3670.629.
Fossil tracks of charged particles have been observed in minerals separated from the Vaca Muerta mesosiderite. Irradiation of samples of the meteorite with thermal neutrons in a nuclear reactor, together with measurements of track-length distribution, indicate that some of the tracks result from the spontaneous fission of uranium impurities; others, however, are of different origin. Uranium concentrations, which ranged from about 4000 parts per million in a zircon grain to less than 10(-3) parts per million in hypersthene and anorthite, were also measured by irradiating samples with thermal neutrons.
在与 Vaca Muerta 中粒陨石分离的矿物质中观察到带电荷粒子的化石轨迹。在核反应堆中用热中子辐照陨石样品，并测量轨迹长度分布，表明一些轨迹是由铀杂质的自发裂变产生的；然而，其他轨迹则有不同的来源。通过用热中子辐照样品，还测量了铀浓度，范围从锆石晶粒中的约 4000ppm 到辉石和钙长石中的小于 10(-3)ppm。
