Proton- and⁴He-ion-induced L-shell ionization of Pt, Pb and Bi

Abstract

L-shell x-ray production cross sections on selected heavy elements (Pt, Pb and Bi), some of which are of great importance from a biological point of view, have been measured by proton and 4He ion impact at energies ranging between 0.3 and 3.2 MeV and between 0.6 and 1.8 MeV, respectively. The data have been compared with the results of other laboratories, whenever existing, obtaining an overall good agreement. L-subshell ionization cross sections have been extracted and compared with the predictions of various theoretical approximations in the description of the ionization process. The disagreement observed at low values of the reduced velocity parameter LR between the data and the predictions of the ECPSSR model is significantly reduced by using a united-atom approximation in the treatment of the binding correction, as suggested by our group (ECPSSR-UA), and by replacing the screened hydrogen-like wavefunctions with the more realistic Dirac-Hartree-Slater ones. The application of a modified Coulomb deflection correction, recently suggested by our group, has further reduced the remaining discrepancies, predominantly in the case of impinging 4He ions.

4He-induced L X-ray production cross sections in Pt and Bi

“…3, we see good agreement between the present results and those of Balsamo et al [10]. For the comparison of theoretical values with our results and other data, good agreement can be seen for L a and L tot .…”

“…Fig. 2 shows complementarity between our results of X-ray production cross sections and those of Balsamo et al [10] for the L a , L b and L c lines. Comparison between our experimental data and the ECPSSR values shows good agreement for L a and L tot .…”

“…2 and 3 for Pt and Bi, respectively. Our data are compared with those of Balsamo et al [10] and with the calculations by the ECPSSR model [5].…”

“…This disagreement came originally from an underestimation of the L b and L c X-ray production cross sections. The compilation of data on 4 He-induced X-ray emission is still incomplete as can be seen in [9][10][11]. L shell X-ray production cross sections are lacking for L a , L b and L c lines at energies above 1.8 MeV for Pt and Bi.…”

Quality Assurance Challenges in X-ray Emission Based Analyses, the Advantage of Digital Signal Processing

“…There is surprisingly large scatter in these data, 8 a clear indication of methodological problems. Different investigators reach different results.…”