COSTER-KRONIG YIELDS OF THE XE-54 L-SUBSHELLS MEASURED THROUGH SYNCHROTRON PHOTOIONIZATION

The method of selective photoionization of individual subshells by mon ochromatized synchrotron radiation has been employed to measure all Co ster-Kronig yields of the Xe-54 L subshells. The energy of the primary radiation was set at about 50 energy points in the range of the L edg es. At each setting, the induced Xe L fluorescence and the induced Ar K fluorescence (used for normalization purposes) were recorded simulta neously by a Si(Li) detector. Both Xe and Ar were in the gaseous state . The recorded fluorescence spectra were carefully analyzed with prope r modeling of the line tailing due to the intrinsic line profile and t he detector line shape. The Coster-Kronig yields were derived by fitti ng the measured fluorescence intensities versus primary energy with th e photoelectric cross sections. The derived yields are sensitive to th e precise dependence of the cross sections on primary energy. Evaluati ons have been performed assuming a smooth power-law dependence and emp loying corrections for electron-correlation effects, which were estima ted from comparative calculations in the independent-particle approxim ation and linear-response approximation models. Still, the uncertainti es of the correlation effects constitute the main contribution to the uncertainties of the derived Coster-Kronig yields. The finally adopted values are f(12)=0.12+/-0.03, f(13)=0.23+/-0.04, and f(23)=0.14+/-0.0 2.