Characteristics of Cerenkov Images Produced by Primary Photons and Hadrons and by Local Muons

Abstract

The appearance of Cerenkov light sources in high-altitude air showers (and background signals due to local muons) has been calculated and typical differences between the images of showers induced by gamma rays and by background nucleons are illustrated by a few examples of high-resolution images. It seems that much higher resolution than is currently employed in detectors would be advantageous. The Cerenkov angle plays little part in the shape of the image: one almost has a simple geometrical perspective view of the shower in space. This perspective view determines what is seen when a shower is viewed from more than one detector position. The lateral distribution of light is then relevant: this is erratic in TeV nucleonic showers, where individual penetrating particles produce local light peaks.