L-shell X-ray production cross sections in 26Fe, 28Ni, 29Cu, 30Zn, 31Ga and 32Ge by 0.5 to 8.0 MeV He ions

Abstract

L-shell X-ray production cross sections by 0.5 to 5.0 MeV He+ and 5.5 to 8.0 MeV He2+ ions are reported for elements with X-rays between 0.70 keV and 1.19 keV. Thin targets of 26Fe, 28Ni, 29Cu, 30Zn, 31Ga and 32Ge 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 bremsstrahlung method. 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 used-on the average about 5% below the ECPSSR. At the lowest velocity, 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 account for intrashell transitions and recently proposed modifications to the ECPSSR treatment of the binding effect give larger cross sections than the ECPSSR and hence-when multiple-hole fluorescence yields are used-they are in larger disagreement with our measurements.