Bremsstrahlung Cross-Section Measurements at Incident Electron Energies of 1.0, 1.7, and 2.5 MeV

Measurements of electron-bremsstrahlung cross sections have been made for incident electron energies of 1.0, 1.7, and 2.5 MeV and targets of Al, Cu, Sn, and Au. Data are included at angles of observation from 0^∘{} to a limiting angle including more than 90% of the total emitted bremsstrahlung at each incident electron energy. The present measurements are lower than the results of Motz for Al and Au at 1.0 MeV; however, the present results at 2.5 MeV agree with the results of Starfelt and Koch at 2.72 MeV. Comparison with the Born approximation indicates that the experimental cross sections are larger than predicted near the high frequency limit. This effect increases with atomic number at a given energy but decreases with energy, as expected.