Fissile material isotopic composition by γ-ray spectra

This work is a physical feasibility study of nondestructive detection and identification of fissile material. The key point of the technique is the extraction of other useful information through the measurement of characteristic γ radiation emitted spontaneously from the nuclear fissile material. Using numerical simulation, this method was tested and the results showed that the isotopic composition and other characteristic information can be extracted from the measured γ-ray spectra with an accuracy better than 2%. Also, the present study indicated that the sample self-absorption correction is a crucial factor to improve the accuracy of the calculations and we present a simplified semi-empirical expression for the sample self-absorption correction of some simple geometric configurations. The method discussed in this paper can be applied to the fissile material safeguarding techniques such as monitoring, verifying, accounting, etc.