Signal Processing for Radiation Detectors

10Digital Radiation Measurement Systems

This chapter is devoted to a general description of the digital radiation measurement systems and the commonly used algorithms in the digital processing of signals from radiation detectors. Our discussion will include the algorithms developed for energy spectroscopy, timing, and pulse‐shape discrimination applications with semiconductor, gaseous, and scintillation detectors.

10.1 Digital Systems

10.1.1 Basics

It was discussed in the previous chapters that all analog pulse processing systems aiming for energy, timing, position, or pulse‐shape measurements practically include an analog and a digital part with an analog‐to‐digital converter (ADC) in between. The analog part takes preamplifier or photomultiplier tube (PMT) signals and processes them, and the outputs are converted to digital values by using devices such as peak‐sensing ADCs or TDCs. The digital part then processes the digital values for purposes such as histogramming, comparisons, etc. In digital signal processing systems, the analog‐to‐digital conversion step takes place as close as possible to the detector, that is, immediately after the preamplifier or PMT and by using a fast and high resolution free‐running ADC that records the signal waveforms as a digital data stream with fixed sampling period. After signal is digitized, a set of algorithms is applied to the sampled signals to extract parameters such as energy, time of arrival, particle types, or the position of interaction. ...