A study of the production of γ-rays in high-energy nuclear interactions I.The energy spectra of nuclear and γ-ray cascades observed at balloon altitudes

Abstract

A composite detector of heavy metal and nuclear emulsion has been used to investigate electromagnetic cascades produced by the cosmic radiation. The stack was exposed on a balloon near the top of the atmosphere for 28h. Approximately 4000 cascades were observed and these were classified as arising from nuclear interactions in the overlying atmosphere, in the detector itself or in a thin graphite layer surrounding the detector. The energies of the cascades were estimated from their electron track density. The energy spectra of the various types of cascades are presented and these are compared with similar measurements made at greater depths in the atmosphere.