Estimation of the plutonium isotopic ratio in a plutonium-beryllium howitzer using gamma spectrometry
The gamma-ray spectrum of a 239PuBe neutron source was analyzed to identify and quantify its isotopic composition. In addition to the previously reported 239Pu isotope, the present work confirms the presence of 240Pu and 241Pu. The isotopes' theoretical masses were computed to be 16.1 g 239Pu, 3.96 g 240Pu, and 1.86 mg 241Pu. Based on these, the 239PuBe neutron howitzer contains 80.24% 239Pu, 19.73% 240Pu, and 0.03% 241Pu. The results will be useful in simulating irradiation systems based on 239PuBe (e.g., low-dose uniform neutron irradiation system) and verifying dose rates and neutron fluxes for various applications such as neutron activation analysis and detector calibration.