GRABGAM: a gamma analysis code for ultra-low-level HPGe spectra

The GRABGAM code was developed for the analysis of ultra-low-level HPGe gamma spectra. The code employs three different size peak-search filters, where the widest is most sensitive for singlet peaks and the narrowest is best for distinguishing multiplet peaks. GRABGAM generates an integral probability F-function for each singlet or multiplet, instead of the usual peak fitting with a differential probability f-function. Because F is defined by the peak data, statistical restraints for peak fitting are reduced; nevertheless, the F-function does provide generic values for peak centroid, full-width at half-maximum, and tail similar to those for a Gaussian formulism. GRABGAM has successfully analyzed over 10,000 sample spectra, and it interfaces with a variety of supplementary codes for deducing detector efficiencies, backgrounds, and quality parameters.