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Experimental results are presented comparing the intensities of the bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on a thick Ag target, measured at forward angles in the range of 0° to 55°. When the data are corrected for attenuation due to photon absorption within the target, the results indicate that the detected radiation is distributed anisotropically only at photon energies k that are approximately equal to the initial energy of the incident electrons E0. The results of our experiments suggest that, as k/E0 → 0, the detected radiation essentially becomes isotropic due primarily to the scattering of electrons within the target. A comparison to the theory of Kissel et al. [At. Data Nucl. Data Tables 28, 381 (1983)] suggests that the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets only when k/E0 ≈ 1. The experimental data also are in approximate agreement with the angular distribution predictions of the Monte Carlo program PENELOPE. [ABSTRACT FROM AUTHOR]

The bremsstrahlung produced by 17.5-keV electrons incident on a 2415 μg/cm2 Ag target has been measured at forward angles in the range 0° to 55° relative to the electron beam. The intensity of the thick-target bremsstrahlung produced is presented on an absolute scale at angles in this range, with corrections for detector efficiency, photon attenuation within the target itself, and other factors. After correction for photon attenuation within the target, the results indicate that bremsstrahlung is essentially isotropic. The experimental data are in approximate agreement with both the predictions of a modified version of the Kramers formula and the Monte Carlo program, penelope. [ABSTRACT FROM AUTHOR]