Photon counting with photodiodes

Abstract

Preliminary results concerning the use of silicon photodiodes designed to be used in the photon counting or Geiger mode are described. These Geiger photodiodes have higher detected quantum efficiency than photomultiplier tubes over the 5000–9000-Å wavelength region and are especially superior at longer wavelengths, although they can only be used in the Geiger mode at relatively low flux rates (<104/sec). Diodes operating in this mode are probably the fastest photon counting detectors in existence. The limitations and properties of Geiger diodes currently available are discussed.