ICRU Report 55, Secondary Electron Spectra from Charged Particle Interactions


ICRU Report No. 55 provides a comprehensive guide to quantitative information about emission of secondary electrons in collisions of fast electrons, protons, alpha particles, and heavier ions with free atoms and molecules and with condensed matter. Explanations of the various mechanisms of ionization are given.

Experimental methods are described, and theoretical techniques are presented for determining total cross sections as well as cross sections differential in the ejection angle and energy of the secondary electrons. The semi-empirical and analytical models given enable the user to make rapid calculations of certain cross sections. Some applications of secondary electron spectra to radiological problems are also described. Data are available for impacts by electrons at energies from a few keV up to 10 keV, for incident protons from a few keV up to 5 MeV, and for heavier particles up to 1000 MeV. Methods are described for extrapolating cross section data to higher energies. The wide variety of targets reviewed include atoms (H, He, Ne, Ar, Kr, Xe, and Hg), molecules (H2 , N2, O2, CO2, H2O, CH4, C2H2, C3H8, C6H6, CH3NH2) and solids (C, Al, Pb, and Au). Some of the calculational methods can be used for all targets for which basic data, such as ionization potentials, are available.