ABSTRACT
This chapter describes the detection and measurement of external ionizing radiation, along with the methods for calibration and testing. The chassis contains a battery-operated power supply for the measurement circuitry, and it has an analog meter display. The ionization chamber has a thin entrance window to permit the detection of beta particles. The basic construction of an ionization chamber, a gas or air-filled chamber with an electrically conducting wall and a central collecting electrode, can also be employed in other detection devices by using a different method of ion collection. A neutron instrument that relies on a different type of detection principle uses a tissue-equivalent plastic proportional counter. The process of thermoluminescence as applied to radiation detection and measurement relies on the behavior of electrons in crystalline solids. A measurement standard may be either a radiation source or a radiation field produced by a radiation-generating device.
