Year
1987
Abstract
The MGA (Multiple Group Analysis) code which we developed several years a.gp required two detectors when analyzing high 241Pu content samples. The isotopic information, which was obtained from the 300-keV regions, can now be obtained equally well from the low-energy region (50-208 keV). This breakthrough was achieved by developing a unique and highly accurate method for delineating the overall \"intrinsic\" efficiency curve, including the plutonium K-shell absorption edge discontinuity. Consequently, the intense 129- and 148-keV peak intensities can now be used reliably in place of the peaks in the 300-keV regions to determine the relative abundances of 239Pu and 241Pu. The 203/208- and 148/152-keV pairs, and all of the intense 94- to 104-keV peaks, are included in the analysis to provide accurate data for the other isotopes of interest.