L-shell vacancy production in Ag, Ta and Au for incident ionsZ 1?10 in the energy range of 0.125?4 MeV/amu

Abstract

Absolute Ag, Ta and Au L-shell X-ray cross sections were measured using protons, 4He, 14N as well as 2~ ions in the energy range of 0.125-4 MeV/amu. By means of single-hole fluorescence yields experimental ionization cross sections were deduced and compared with calculations according to the corrected PWBA model -PWBA(BPCR). With decreasing asymmetry of the collision system the experimental cross sections exceed the predictions of the direct ionization theory. This is caused by an increasing contribution of a competing KL charge exchange mechanism which was investigated in detail for Ne + Ag. The Lapicki and Losonsky capture model was found to fail at energies E < 1 MeV/amu because adiabatic relaxation effects in the projectile K-shell become important. An estimation by means of the Nikitin model led to more physically comprehensible results at the lowest ion velocities investigated. 05

L-subshell ionization of heavy elements by carbon and nitrogen ions of energy 0.4–1.8 MeV/amu

“…0-MeV nitrogen ions were reported by Malhi and Gray [30]. Bauer et al [33] have measured total L-shell x-ray production cross sections for Ag, Ta, and Au targets for nitrogen ion energies 0.125 -4.0…”

L sub-shell cross sections for proton impact on selected 4d transition elements

“…Table 1 presents the measured L x-ray production cross sections for these elements bombarded by protons ranging variously from 50 to 300 keV. Figures 1 and 2 show the experiment/theory L sub-shell x-ray cross section ratios using the Krause database in calculating the theoretical ECPSSR and ECPSSR-UA x-ray production cross sections, and using the relative transition rates from Campbell and Wang [22] according to equations ( 5)- (7). ECPSSR and ECPSSR-UA L sub-shell x-ray production cross sections were calculated from the most recent version of ISICS [10].…”

“…Presented here are measurements of L sub-shell x-ray production cross sections for proton impact on thick targets of Y, Zr, Nb, Mo, Rh, Pd, Ag and Sn in the 50-300 keV energy range. Previous measurements by others [3][4][5][6][7][8] in this energy range have only reported total L-shell cross sections for these elements. The results are compared with ECPSSR and ECPSSR-UA theory and with different atomic parameter databases, by use of the computer code ISICS [9,10].…”