A novel approach for modelling the cluster detector and the SPI spectrometer

A probabilistic approach has been presented in six recent papers (R Kshetri, J. Instrum . 2012 7 P04008; ibid ., P07006; ibid ., P07008; ibid ., P08015; ibid ., P12007; Appl. Radiat. Isotopes 2013 75 30) for modelling a general composite detector. In this paper, a simplistic view has been presented on the application of our formalism to composite detectors consisting of hexagonal closely packed encapsulated HPGe detector modules. We have presented modified calculations for the peak-to-total (PT) and peak-to-background (PB) ratios of the cluster and spectrometer for integral satellite (SPI) for the first time considering up to four-fold events. Instead of using an empirical method or simulation, we present a novel approach for calculating the peak-to-total ratio of the SPI spectrometer for high γ energies. Our work can provide guidance for designing new composite detectors and for performing experimental studies with the SPI spectrometer for high-energy γ -rays.