Field ion microscopy of uranium. I. Preliminary results

Aspects of obtaining field ion images of uranium specimens are considered. The stability of uranium tips with respect to mechanlcal tension in the field ion microscope has been investigated. The best results were obtained when using pure argon and the mixture He + 0.5% H/sub 2/ as image gases. Aided by a computer, a model of the field ion image of alpha -uranium and standard stereographic projections for alpha -uranium on the (010), (001) and (110) planes was constructed. This made it possible to index the crystallographic faces on the obtained micrographs. The adduced preliminary results demonstrate that field ion microscopic analysis (in atomic detail) of uranium specimens is possible in principle. (tr-auth)