Improvements in the PC/FRAM isotopic analysis software

A new version of the PC/FRAM* isotopic analysis software is under development at Los Alamos National Laboratory. This version will be optimized for unattended robotic operation in the upgraded ROBOCAL automated calorimetric assay system at the Los Alamos plutonium facility and will automatically analyze samples with no prior knowledge of their isotopic content, presence of internal shielding, or presence of isotopic heterogeneities or interferences, A new physics-based relative-efficiency formalism will enhance performance on weak spectra as well as uranium and mixed oxide in shielded containers. Several other improvements are planned for improved measurement performance for uranium. Corrections for coincidence summing will allow measurements at varying distances, reducing the biases that can arise without these corrections. We will also add an isotopic correlation to predict the (23)6U value, which cannot be directly measured by gamma-ray spectrometry. The new software will also allow the user to correct for nonequilibrium U-238-Pa-234. The software will be structured in the analysis engine/user interface shell form, allowing easier customization for specific user needs.