Compton scattering of 1.12-MeV gamma rays byK-shell electrons of heavy elements

Abstract

A study has been made of the Compton scattering of 1,12-MeV gamma rays by K-shell electrons of tin, tantalum, gold, lead, and thorium. K x rays of target atoms were detected in coincidence with the scattered gamma rays. A careful investigation of false coincidences has been carried out. The ratio der~/do. F of the Kshell electron cross section to the Compton cross section for a free electron at rest was determined at serveral angles between 25' and 120'. The cross-section ratio in the case of gold and thorium is less than 1 at 25', larger than 1 in the neighborhood of 90', and