A multi-parametric waveform analysis of Ge detector signal based on fast ADC digitizing technique

A fast digitizing system was applied to a new waveform analysis of γ-ray spectrometry, where coaxial Ge detector signals were analyzed by a fast ADC (200 MHz/10 bits) combined with a UNIX workstation. Multi-parametric analysis of each pulse waveform has been examined using two parameters: one parameter was a signal risetime (tr) and the other was a shape index (Ra) which describes the convexity or concavity of waveform in the pulse risetime region. A set of two parameters (tr and Ra) can indicate the γ-ray reaction position for one collision event, which agreed well with experiments using a collimated ⁵⁷Co γ-ray source. The selection of multiple scattered events gave a better peak-to-Compton ratio of 128:1, which was 3.4 times higher than the value without this selection