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K-shell x-ray-production cross sections are reported for elements with K-shell x-ray energies between 277 eV (C) and 1487 eV (Al). The x-ray measurements were made with a windowless Si(Li) detector that was calibrated for eKciency by comparing bremsstrahlung spectra from electron bombardment of thin foils of aluminum, silver, and gold with theoretically determined bremsstrahlung spectral distributions.The x-ray-production cross-section measurements are compared to first-order Born and perturbedstationary-state with energy-loss, Coulomb deflection, and relativistic corrections (ECPSSR) ionization theories using single-hole Auorescence yields. The ECPSSR and first-order Born theoretical predictions are, in general, in close agreement with each other and both generally fit the data quite well.

Lshell x-ray production cross sections by 0.5 to 5.0 MeV He" and 5.5 to S.0 MeV He" ionsarereportedForelementswithx-raysbetweenO.~O keV and 1.19 keV.Thintargets ofZFe, rsNi, & I , ,@Zn, ,,Ga and ,>Ge were manufactured using a cleaning process that reduced the level of light element impurities. The x-rays were measured with a windowless Si(Li) detector, whose efficiency was determined by the atomic-field bremsstrahlungmethod.The data are compared to the predictions of the first-order Born and the ECPSSR theories using the single-and multiple-hole fluorescence yields. The ECPSSR theory is clearly superior to the first-order Born approximation, although the data fall-when single-hole fluorescence yields are u s e d -m the average about S0/~below the ECFSSR. At the lowestvelocity, however, on the average this theory underestimates our measurements by 15% when single-hole fluorescence yields are employed. When multiple-hole fluorescence yields are used, the theory is within 3% of the averaged data at the lowest ion velocity. Coupled-state calculations that acsount for intrashell transitions and recently proposed modifications to the ECPSSR treatment of the binding effect give larger cross sections than the ECPSSR and hencewhen multiple-hole fluorescence yields are used-they are in larger disagreement with our measurements. The measured cross sections are shown to agree reasonably well with the results of our previous investigations, except for very substantial discrepancies at the lowest ion energies. We attribute these diferences to systematic errors in our previous experiments due to the Be window of the Si(Li) detector that resulted in a particularly small signal-tobackground ratio. t LINK Analytical Limited,

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