A Novel Digital Pulse-Shape Analysis for High-Resolution Position-Sensitive Gamma-Ray Spectroscopy

A novel digital pulse-shape analysis (DPSA) was performed for high-resolution position-sensitive gamma-ray spectroscopy with coaxial-type high-purity germanium (HpGe) detectors. The DPSA consisted of two stages that determined the pulse height, the interaction point and the start time by using the chi-square fitting the digitally recorded pulse shapes with calculated shapes. As the DPSA was applied to gamma-ray spectroscopy using HpGe coaxial detectors, we obtained the energy spectra, the time-difference spectra and the interaction depth profiles for the gamma rays emitted from Ba-133 and Na-22 standard sources. The efficiency of the spectroscopic analysis using the DPSA was compared with that using a conventional analog signal process (CASP). Furthermore, we determined the half-lifetime of the first excited state in Cs-133 by using the DPSA.