Dependence of 50- and 100-keV Bremsstrahlung on Target Thickness, Atomic Number, and Geometric Factors

Experimental data have been obtained for the bremsstrahlung spectra produced with 50- and 100-keV electrons incident on different targets. The spectrum per unit solid angle per incident electron is measured for photon emission angles of 30, 70, and 110 deg, for normal and oblique incidence of the electrons on the targets having atomic numbers of 13, 50, and 79, and for four target thicknesses equal to different fractions of the electron range in the given material. Also, results are given for the bremsstrahlung production efficiencies per unit solid angle at a given emission angle. The experimental results at normal incidence show good agreement with the theoretical predictions of Berger and Seltzer, which are based on thin-target bremsstrahlung cross sections and which employ Monte Carlo calculations to account for multiple scattering and energy-loss effects. Similar calculations for other geometries should produce reliable estimates of the emitted bremsstrahlung spectra in this same energy region.