48. Radiation Detection

Most radiation related to nuclear properties is outside the visible part of the electromagnetic spectrum or involves submicroscopic particles, hence is invisible. Detectors – devices to sense the radiation, and perhaps measure its properties – are essential. The emphasis in research has moved from the characterization of radioactivity, through simple nuclear reactions, to explorations of the extremes of nuclear matter, but the central importance of suitable radiation detectors has persisted. This chapter emphasizes detectors associated with measurements of radioactivity, as opposed to nuclear reactions. Thus, much of the current creative work is excluded, but otherwise the scope of these volumes would at least double. Detectors are classified broadly as based on ionization of gases, conduction in semiconductors, or scintillation. The concluding section is an introduction to systems based on two or more components of one of these basic types.