The Computation of Photon Radiation Induced Electron Emission

Abstract

In recent years a variety of models have been developed for the computation of the photon radiation-induced electron emission from matter, ranging from pure Monte Carlo models, which while rigorous are quite costly for application as an engineering tool, to pure analytical models, which while convenient and inexpensive have strictly limited ranges of validity. The limitations of analytical models due to the neglect of Auger and secondary contributions to the emission current and due to the neglect of electron multiple scattering in the emission calculation are examined in this paper. A one-dimensional model is developed for predicting the relative magnitudes of the photoelectron, Compton, Auger, and secondary electron contributions to the emission current, and the model predictions are correlated with experimental data. It is concluded that a generally applicable emission model should include treatment of the Auger and secondary electrons as well as the photoelectrons and Compton electrons. The significance of electron multiple scattering in the calculation of the emission is examined through comparisons of analytical, Monte Carlo, and experimental data. It is concluded that while multiple scattering may be neglected in the calculation of forward emission efficiency, it must not be neglected in the calculation of backward emission effeciency or angular distribution of emission. An alternative emission computational model is introduced which utilizes a synthesis of analytical and Monte Carlo techniques. Comparisons of the model predictions to experimental data for forward and backward emission efficiency, energy spectrum, and angular distribution are included.