High-Frequency Region of the Spectrum of Electron and Positron Bremsstrahlung

The cross section for a bremsstrahlung process in which almost all the energy of an incident high-energy electron is transferred to the photon is calculated analytically, using techniques previously developed for atomic photoeffect. Only terms of relative orders a⁴, a²q², and q⁴ are neglected, where a≡Ze² and q is the momentum of the outgoing low-energy electron (with =c=mₑ=1). Similar results are obtained for positron bremsstrahlung and pair production; previous work on the photoeffect is extended. The accuracy of these predictions is discussed, and they are compared with experiments.