Target-thickness Dependence of Bremsstrahlung from Solid Al and Au Films

The results of a study of the target thickness-dependence of bremsstrahlung from solid films are presented, along with comparisons of the ratios of the data for different target thicknesses with the ratios obtained using the Monte Carlo code PENELOPE. The electron beam energy used in the experiments is $\sim $55 keV and bremsstrahlung is observed at an angle of 90$^{o}$. The targets used were made of gold and aluminum, with thicknesses ranging from 30 $\mu $g/cm$^{2}$ (where single interaction conditions apply) to about twice the electron range (where a multiple interaction model applies). The purpose of the study is to observe the transition from thin to thick film spectra and to investigate whether the polarization bremsstrahlung contribution is suppresses in solid film targets.