L-shell X-ray production cross sections for Au, Pb and U by proton, deuteron and alpha impact

Abstract

Experimental proton-, deuteron- and alpha-induced Lalpha , Lbeta , Lgamma and Ll X-ray production absolute cross section values for the elements Au, Pb and U in the incident energy range 0.2-0.45 MeV u-1 for alphas and 0.2-0.9 MeV u-1 for protons and deuterons are presented. Accurate values for ratios of production cross sections of the same L line by different projectiles and for intensity ratios of different L lines excited by the same projectile are obtained from the present results, experimental conditions being kept constant for the various measurements. The experimental results are compared with theory using the procedure recommended by Brandt and Lapicki (1979, 1981) to obtain theoretical values for the ionisation cross sections allowing for relativistic, binding, Coulomb and energy loss effects. The absolute experimental and theoretical cross section values show degrees of agreement which are different for the various L lines and also depend on the projectile and its velocity. From the values of the cross section ratios for production of the same L line by different projectiles it is argued that the proposed correction for the binding effect is too large and that for the Coulomb and energy loss effects still needs to be improved at the lowest velocities. The intensity ratios of different L lines produced by the same projectile seem to show that the usually accepted values of fluorescence and Coster-Kronig yields are unable to produce agreement with experiment.