Determination of Pu-239 content in Pu–Be neutron sources using Gamma-ray spectrometry

The need to determine the content of plutonium in Pu–Be neutron sources of Russian provenience arises from the administrative regulations applying to nuclear materials. The determination of a plutonium (all isotopes) amount was based on the measurement of an activity Pu-239. Gamma-ray spectrometry with semiconductor detector HPGe was applied. The determination of plutonium (all isotopes) amount was based on the measurement of Pu-239 activity by means of Gamma-ray spectrometry with semiconductor detector HPGe. Gamma lines of radionuclides Am-241, Pu-238, Pu-239 and Pu-241 were detected in spectra. Detection efficiencies were calculated by Monte Carlo method using MCNP4A code. Computations were done for several hypothetical plutonium amounts. Activities determined from peak areas of 129 and 413 keV photons emitted from Pu-239 were confronted. The right amount was established under the condition of equality of both activities.