Development of Photon Sensors with Ultra-high Sensitivity

Abstract

Photon detection has been playing an important role in the various fields of scientific researches. Among many photon detectors developed so far, an electron bombardment (EB) photon sensor attracts wider interests these days. In the sensor, the photo electrons emitted from the photocathode are accelerated and focused on the semiconductor device, where the electrons would generate thousands of electron-hole pairs corresponding to the energy of the bombarded electrons. Thanks to the large gain of this process with less fluctuation, the sensor has a very good sensitivity for single photon counting. In this article, the operational principle and its key elements of the sensor are described together with some performances of the sensors developed recently.