New method of digital waveform analysis of signals from segmented Ge detectors

We study digitized waveforms ($f(t_i)$) from a segmented Ge detector in CNS GRAPE [1], by means of $n$-th ``moments'', $\sum_{i} t^n f(t_i) / \sum_i f(t_i)$ . Nine sets of digitized data of the signal from 3 $\times$ 3 cathodes were recorded by using ADC with 105 MHz sampling [2]. The purpose of the present study is deducing essential information from about 1K-byte waveform data with a simple algorithm to determine the interaction position of $\gamma$-ray. The moments from $n=0$ to $3$ are examined. The characteristics of the moments will be discussed as a function of the hit position. In the preliminary analysis, it shows that the root-mean-square ($n$=2) and the skewness ($n$=3) vary in wide ranges with changing the hit position. \\[4pt] [1] S.Shimoura, Nucl. Inst. and Meth. A 525 (2004) 188.\\[0pt] [2] T.Fukuchi et al., CNS Annual Report 2006 (2006) 77.