SILICON AVALANCHE DIODES AS DETECTORS FOR GAMMA RADIATION

A semiconductor gamma detector is described which can be considered the solid-state analogue of the Geiger-Müller counter. The detector is an alloyed silicon diode operated in its breakdown region. Gamma detection occurs by diffusion of minority carriers from the ionization track of the fast electron to the avalanche channel, where a breakdown pulse is triggered (typical pulse height: 25 μA). The small counting volume in connection with a thermally produced background" pulse-rate establishes a lower limit of measurable dose rates at about 20 rad/h. The usable range of dose rates can embrace 5 decades. Calculations and experimental data of the energy dependence are presented. © 1968."