Absorption and noise in cesium iodide x-ray image intensifiers

Abstract

The measured and theoretically predicted values of detective quantum efficiency (DQE) for a CsI X-ray image intensifier are compared for 9 monoenergetic beams of X-rays. The agreement between measurement and theory of better than .+-. 5% indicates that a sound understanding of the physical parameters controlling the DQE have been obtained. The fraction of K-fluorescent X-rays escaping from the input phosphor evidently is independent of incident energy. The number of electrons released within the X-ray image intensifier (XRII) by an incident X-ray was measured. The mechanism for energy broadening within the XRII is shown to be predominantly the limited number of electrons and not light absorption.