ON SENSITIVITY OF GAS-DISCHARGE DETECTORS TO LIGHT

A gas-discharge counter with a cathode of semitransparent aluminized m ylar film is found to be sensitive to visible light. Time spectrum of counter signals caused by a pulsed light source showed that the sensit ivity to light is due to cathode photoeffect. The proposed mechanism f or this phenomenon is based on a decrease in the electronic work funct ion of the aluminium cathode by the electric field in conformity with the Schottky-law, Positive ions arising in the gas discharge are depos ited on the dielectric oxide film on the aluminium cathode surface. Th e resulting surface charge produces a strong electric field at the cat hode (E(sigma) similar to 10(7) V/cm) which decreases the work functio n and shifts the red boundary of photoeffect on the aluminium from the UV to visible region of the spectrum. The effect of this phenomenon o n the operation of gas-discharge detectors and its possible applicatio ns are discussed.