Bremsstrahlung Spectrum of 600 MeV Positrons and Electrons in Propane

Abstract

The high-energy end of the bremsstrahlung spectrum of 600 MeV electrons and positrons has been studied in a propane bubble chamber. The cross-section for the emission of a photon having more than 88% of the initial electron energy is found to be larger than the theoretical calculations. The difference is (4.6 ± 3.7)% for positrons and (17.3±4.8)% for electrons. The ratio of positron to electron bremsstrahlung is 0.89 ±+ 0.04. If only events where the photon has > 98% of the initial energy are considered, then the measured ratio of crosssections is 0.82 ± 0.12.