The detection of uranium is of greatest interest because it is the type of nuclear material so far mostly encountered in illicit trafficking. However, its detection and identification is generally difficult and sometimes even impossible, especially if the uranium is highly enriched and concealed under shielding. In this paper we will present a complete study of the uranium gamma spectra seen by a typical hand-held monitor with a NaI detector through various shielding materials. Resulting gamma spectra were both obtained experimentally and by Monte Carlo simulation studies. From a review of the spectral data we propose a new approach for the identification of uranium which makes also use of the shape of the measured gamma continuum observed from shielded uranium. This complementary information can be helpful in cases of poor statistical data for the full photon energy peaks of uranium gamma rays. The applicability and limitations of this analysis approach will be discussed.

ABOUSAHL Said;  VAN BELLE Pieter;  RAGAN P.;  PYLKITE L.;  BAGI J.;  ARLT R.; 

2005-12-19

European Safeguards Research and Development Association (ESARDA)

JRC30899

https://publications.jrc.ec.europa.eu/repository/handle/JRC30899,