The energy spectra and the quantum efficiencies of electrons emitted from the metallic elements irradiated by 60Co gamma rays

Abstract

The energy spectra, angular distributions, and the absolute quantum efficiencies of forward emission electrons from 60Co γ-ray irradiated metallic elements have been measured using a double focusing β-ray spectrometer. Samples measured were C, Al, Cu, Mo, Sn, W, and Pb. Their thicknesses were chosen about equal to the maximum range of a 1.33 Mev photoelectron so as to ensure electron equilibrium. Similar spectral shapes were observed for samples with similar atomic numbers, but energy spectrum for the large atomic number sample was different from the small atomic number one. Photoelectron peaks were observed in the spectra for W and Pb. An empirical equation which gives the quantum efficiency as the function of atomic number was obtained. The efficiencies computed from this equation were in good agreement with experimental results and numerical calculations.