I. The Fundamental Limits of Information Content in Solid State Image Intensifying Panels Compared with Other Intensifying Systems
J. F. Fowler · British Journal of Radiology · 1960
The principles of operation of solid state image intensifying panels have been described else-where (Kazen and Nicoll, 1955; Diemer, Klasens and Van Santen, 1955; Henderson, 1958). Fowler (1959) and Henderson (1960) have given experimental results for panels made by Thorn Electrical Industries and designed jointly with King's College Hospital Physics Department. In the present paper, the limits of information content of the images obtained with solid state panels will be discussed, in order to make comparisons with electrostatic intensifiers and with television systems. We wish to examine the fundamental limitations of the various systems, in order to see how useful the solid state panels might be. The emission and absorption of quanta are random processes, and are subject to statistical fluctuations which can be predicted. Rose (1948) showed that the standard deviation of the fluctuations (or “noise”) is nearly equal to √N, where N is the number of information carriers (i.e. quanta or particles) collected per unit time for unit area of the image. All the stages of a viewing system contribute to the total noise, but if the number of useful quanta at any one stage in the system is considerably less than at any of the other stages, this stage will set the signal-to-noise ratio for the whole system. The random fluctuations will determine the degree of resolution attainable as follows.