Low-light-level television

The paper summarizes the fundamental limitations set by the available light and the efficiency of the photocathodes available at present, and considers in detail how closely existing types of camera tube and image intensifier can approach this fundamental limit. There are many possibilities, from the simple adaptation of existing broadcast tubes to the combination of high-gain image intensifiers with conventional television camera tubes, either by optic or fibre optic coupling or by building the two into the same vacuum envelope. Between these, one may say that the problems of low-light-level television are well on the way to being solved within the limits set by the factors already referred to.