Comparison between thorium and uranium fission track diameters in glass

Comparisons between diameters of uranium and thorium neutron induced fission tracks in glass made possible to test indirectly the hypothesis that observation efficiency of spontaneous 238U and induced 235U fission tracks may be considered the same. The sources of fission fragments were uranium and thorium thin films irradiated with neutrons with and without Cd-cover. After irradiation, the glasses were etched for 50 s by HF 24% at 15∘C followed by another etching for 30 s in same conditions. Diameters were measured after each chemical etching. Only tracks presenting a ratio between the longer and shorter diameters lesser than 1.1 have been analyzed. The results indicates the hypothesis is valid.