Neutron spectroscopy of plutonium oxide using matrix unfolding approach

The knowledge of a neutron energy spectrum is extremely valuable in nuclear non-proliferation and safeguards applications. Unfortunately, conventional gas and fission-type detectors are not adapted to determine incident neutron energy. As a result, a matrix inversion technique was implemented to generate desirable and consistent neutron energy spectra from an EJ-309 liquid scintillator. To overcome the ill-posed unfolded solutions, the method of sequential least squares is reviewed briefly, and the conditions under which it is used are stated. From the analysis, unfolded energy spectra solutions of five distinct PuO2 fuel samples and a 252Cf source are presented and compared to the simulated unfolded and reference energy distributions.