X-Ray Detection by Channel Electron Multipliers

Abstract

X-Rays may be detected by channel multipliers and this presents the possibility of very small radiation detectors. It may be that the channel multiplier has an application to X-ray detection in very confined spaces where larger devices cannot be introduced. It has a rather low detection efficiency but nevertheless may give quite appreciable count-rates at radiation intensities which can be measured easily only by much larger detectors. A channel electron multiplier is a channel or tube of suitable material with a length-to-diameter ratio of between 30: 1 and 100: 1, and between the ends of which a suitable potential is established. A typical channel multiplier has an internal diameter of about 1 mm and a length of 50 mm. Since channel multipliers are able to detect X-rays and to multiply electrons it is natural to think of making them quite small and bundling a lot together so as to provide a means of coherent image intensification. Nevertheless for the purposes of detecting diagnostic X-rays for image formation the detection efficiency of a matrix is probably much too low; it would be preferable to have detection efficiency of the order of 20-30%. It believes that this device would represent an improvement on existing X-ray intensifiers because it would give a full-size picture with as much brightness intensification as is necessary.