RELATIVE SHAPE OF THE BREMSSTRAHLUNG-PHOTON ENERGY-SPECTRUM FROM 7.0-KEV ELECTRONS ON AG AND AU

We have measured the relative shape of the bremsstrahlung-photon energy spectrum from 7.0-keV electrons incident on Ag and Au targets; the targets are thick enough to stop the incident electrons, yet thin enough to transmit a substantial fraction of the radiated photons. Our results for the ratio of double differential cross sections for the bremsstrahlung-photon emission from Ag and Au at 90 degrees to the incident electron beam direction are found to yield excellent agreement with Pratt's theoretical prediction [Comments At. Mol. Phys. 10, 121 (1981); Electron Bremsstrahlung X80: Theory and Recent Developments, Proceedings of the International Conference on X-ray Processes and Inner Shell Ionization, Stirling, Scotland, 1980, edited by D. J. Fabian, H. Kleinpoppen, and L. M. Watson (Plenum, New York, 1981)] on the relative shape of the spectrum; however, the thick-target effect introduces a discrepancy between experiment and theory of about 20%. Also, the calculated absolute efficiency of the detector employed using the theoretical bremsstrahlung cross sections is found to agree with the normalization to the radioactive source within the uncertainty of about 20% in the target thickness.