Improvement of the Compton suppression ratio of a standard BGO suppressor system by a digital pulse shape analysis

We have applied a digital pulse shape analysis (DPSA) to Compton suppression for a high-purity coaxial germanium detector (HPGe) as a means of verifying the DPSA method that we have recently developed to extract information for the interaction positions of gamma rays in semiconductor detectors. Our DPSA method is based on chi-square fitting the measured pulse shapes to the calculated ones obtained by the weighting potential method. In order to investigate the performance of the Compton suppression technique using our DPSA method, we have extracted the experimental peak-to-total (P/T) ratios for 662-keV gamma rays emitted from a 137Cs standard source. The experimental P/T ratios were compared with the ones obtained by a conventional BGO suppressor system. Applying the Compton suppression technique using the DPSA method to the BGO suppression system, we could also improve the P/T ratios. The experimental results were in good accord with the ones obtained by a Monte Carlo simulation.