ČCerenkov radiation of extensive air showers

Abstract

Short light flashes superimposed on the buckground of the night sky glow, correlated with the passage of cosmic rays in the atmosphere, were first detected in 1952. It was established that at least some of these flashes were caused by Cherenkov radiation of extensive air showers. Further experiments were condncted in the Pamir mountains (altitude 356 m) in the autumn of 1955. The purpose of this investigation wss to study the lateral distribation of the light flux relative to the core of the showers and also to determine the relation between the intensity of the light flashes and the size of the shower. The experimental arrangement included an optical receiver that registered the light flashes and a Geiger counter hodoscope. Two series of measurements were made. The semsitivity of the light receivers was adfusted so that about 100 pulses per hour were registered. On an average, each flash was accompanied by triggering of 20 hodoscope counters, while the number of cases when no counter was triggered was 4%. Thus it was established that pactically all light flashes of a given intensity were produced by extensive air showers. (A.C.)