Signal Processing for Radiation Detectors

5Pulse Counting and Current Measurements

Pulse processing systems aiming to measure the energy spectrum of radiation particles were discussed in the previous chapter. There are also important applications such as medical imaging and radiological protection that only require the intensity or the number of radiation particles regardless of the precise value of particle energy. This chapter is devoted to radiation intensity measurement systems through pulse counting, current mode, and Campbell’s mode operations.

5.1 Background

The output signal of a radiation detector consists of a series of current pulses where each pulse represents the interaction of a nuclear particle with the detector. The readout of the output signals can be performed in different ways. So far we have described the readout of output signals based on the individual readout of the pulses. This mode of operation is called pulse mode operation, where the output of the front‐end electronics is a series of pulses separated or resolved in time where from each pulse information such as energy and arrival time of the events can be extracted. However, in many pulse mode operations, only the number of particles striking the detector is required, and thus one can simply count the individual pulses. Such detection system is referred to as a pulse counting system. The number of counts is usually determined in a certain period of time from which the average counting rate or intensity of radiation can be determined. The measurement ...