Measurement requirements and front-end design rules for gamma-ray tracking in large-volume germanium detectors through pulse-shape analysis

In this paper we address the design of a mixed analogue-digital processor for pulse-shape analysis of signals delivered by large volume High-Purity-Germanium (HPGe) detectors for gamma-ray spectroscopy. The information to be extracted from pulse-shape analysis is the position of the interaction of the gamma photon inside the detector. We discuss the structure of the measurement apparatus and the required characteristics of its components, with a special emphasis on the resolution and sampling frequency of the analogue-to-digital converter (ADC). We also address the problem of the occurrence time estimate of the events, which is strictly related to the pulse shape. A modular hardware solution for pulse-shape measurements is proposed.