Theoretical Analysis of the Photon-Energy Dependence of the Ionization Detector Used in the CT System

Characteristics of the ionization detector used in the CT system are theoretically analysed. The dependence of output from the ionization detector on photon energy is derived. Relations between the output characteristics and geometrical parameters such as electrode separation, electrode length, and gas pressure are numerically calculated for the case of xenon ionization detectors. Application of the calculated results to the design of the ionization chamber is suggested.