Silicon electron multiplication (SEM) camera tube

A low-light-level television camera tube has been realized, which incorporates a silicon electron multiplication (SEM) target. Image electrons liberated from the photocathode bombard the target, causing an electronic amplification of several thousand, as well as electronic charge storage. The SEM tube shows a limiting sensitivity at photocathode illumination on the order of 10^-5lx, and approaches the picture degradation problem due to quantum fluctuation. Further degradation of the picture is observed by addition of an image intensifier tube to the SEM tube, and also in the case of an X-ray image pickup using the SEM camera with phosphor screen. The SEM tube can scarcely be injured by the exposure to a strong light.