Angular distribution of thick-target bremsstrahlung produced by electrons with initial energiesranging from 10 to 20 keV incident on Ag

摘要

Experimental results are presented comparing the intensities of the bremsstrahlung produced by electrons withinitial energies ranging from 10 to 20 keV incident on a thick Ag target, measured at forward angles in the rangeof 0° to 55°. When the data are corrected for attenuation due to photon absorption within the target, the resultsindicate that the detected radiation is distributed anisotropically only at photon energies k that are approximatelyequal to the initial energy of the incident electrons E_0.The results of our experiments suggest that, ask/E_0→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 angulardistribution 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/E_0≈1. The experimentaldata also are in approximate agreement with the angular distribution predictions of the Monte Carlo program PENELOPE.