A Phototube Using a Semiconductor Diode as the Multiplier Element

A phototube has been developed with a semiconductor diode as the multiplier element. The tube has an electron gain of 1200 at 5 keV and has a linear output current in the 6-A range with a dynamic range between 107 and 108. A description is given of the fabrication of the shallow-diffused p-n junction diodes and their use in sealed envelopes with a cesium-antimonide photocathode. Also included is a discussion of the electrostatic lens for focusing the photoelectron beam to the window of the diode, and of the overall operation of the tube.