Year
2004
Abstract
Np analysis has historically relied upon the Pa/Np secular equilibrium for quantitative results. The Savannah River Site has recently undertaken a mission concerning Np. In this application, Np is separated from Pa, packaged, possibly mixed with other batches, and assayed. The fresh separation and mixing of batches prevents the use of the Pa133 prodigy peaks for assay. This effort was a developmental project novel in the DOE complex. This paper will discuss the challenges encountered in the design of instrumentation to assay Np directly. The most abundant Np peak that is unfettered by Pa prodigy, Am, or other SNM materials is the 29.6keV. Quantitative measurement of such a low energy peak presents significant problems with attenuation, Compton effects, and other such issues that arise while trying to maximize the effects of low energy peaks. The solutions rely on exploiting the “tried and true” methods with regard to shielding, detector technology, and calibration techniques, but with a very low energy perspective. The results are intriguing and, with some assumptions regarding sample homogeneity, quantitative within normal MC&A statistics.