Investigation Into Image Intensification Technology

Abstract

It is an detect ability of an image by the statistical fluctuations resulting from the quantum nature of light are analyzed and the efficiency of the photoelectric effect as a detector of optical images is compared with that of the photographic effect. The possible methods of using the photoelectric effect for image detection are enumerated and it is pointed out that this review deals only with those image intensifiers using free electrons. The possible light gain to be had from a simple photocathode-phosphor image tube and gives the reasons for its failure to reach the ideal performance. The methods employed to enable these tubes to be operated at high gain without undue background and to enable the output light to be used efficiently are described. The techniques developed allow the electron image to be projected through a thin window on to a fine grained photographic film external to the tube. the number of electrons is multiplied by a large factor before they are accelerated and detected. Three methods are described: firstly, the cascaded phosphor-photocathode screen intensifier, secondly, the transmission secondary-emission multiplying screen method, and thirdly, the channelled electron-image multiplier.