Lateral and angular structure of electromagnetic cascades

Abstract

Measurements of electromagnetic cascades have been made in nuclear emulsions. Six cascades were measured in the Brawley stack (pure emulsion) and four in the SSS stack (lead–emulsion sandwich). The results show that the validity of the core approximation appears to range up to 7 × 10−2 radiation lengths, the core approximation of the angular distribution is valid to an angle of the order of 2°, and the sandwich structure of the SSS stack had no influence on the validity of the core approximation. A law for the mixed radial–angular distribution is given in one special case.