ABSTRACT
This chapter discusses the following broad subjects: definition of differential and integral spectra, energy resolution of the detector and function of a multichannel analyser. To determine the energy spectrum of particles emitted by a source, one measures, with the help of a detector and appropriate electronics, the pulse-height distribution produced by these particles. Charged particles deposit all their energy in the detector, as long as their range is shorter than the size of the detector. The quality of the performance of a detection system used for energy measurements is characterized by the width of the pulse-height distribution obtained with particles of the same energy. To discuss the effect of the statistical fluctuations on energy resolution, consider a mono-energetic source of charged particles being detected by a silicon semiconductor detector. The effect of incomplete charge collection in gas-filled detectors is small compared to the effect of the statistical fluctuations.
