Development of Pile-up Separation Method Using Digital Signal Processing

Abstract

A new method was developed for separation of pile-up signals by means of pulse shape fitting for the signals which were acquired using a digital signal processing technique. The technique was applied for a high purity germanium (HPGe) detector but can be applied various radiation detectors. In the present method, in addition to linear amplifiers for spectrum measurement, another amplifier with short shaping time is used to derive information on the number of pulses piled up and their timing sequences. Since most of the pulse shapes from HPGe proved to be reproduced with the same pulse shape, we could fit the pile-up signals on the basis of pulse shape, number and the timing between pulses. The method can reconstruct each pulse even for multiple pile-up events without count loss with short analysis time. It enables to correct distortion of an energy spectrum of the HPGe detector and improve the energy resolution.