Image Intensifier Spark Tube

A spark chamber is designed for photographic recording of single electrons from the photocathode of a single-stage image intensifier. The chamber has two high-resistance Nesa layers as the electrodes; the first layer is deposited on the outside of the mesh-supported thin mica window, and the second on the inner surface of the chamber end-window. The voltage applied to the chamber is a damped r-f oscillation of approximates 50 Mc. Very many simultaneous ionizing events can be detected with high efficiency, and a more uniform distribution of light intensity is also obtained. The results of a test with cosmic rays are described.