Experimental determination of cross sections forK-shell ionization by electron impact for C, O, Al, Si, and Ti

Abstract

Cross sections for K-shell ionization by electron impact were determined from films of Al, Si, and Ti and their oxides deposited on carbon substrates, for incident energies between 2.5 and 25 keV. The spectral processing of the x-ray emission spectra took into account corrections due to the presence of a spontaneous oxide layer formed on the monoelemental films and to the supporting material. Carbon K-shell ionization cross sections were determined from the contribution of the substrate to the measured spectra, while for oxygen, data from the three oxide films were taken. The mass thickness of the coatings was characterized by x-ray reflectivity. The results obtained were compared with other experimental data sets, semiempirical approaches, and theoretical models.

X-ray emission from thin plasmas

“…5 for the oxygen isoelectronic sequence. A comparison of some K-shell measurements compiled by Llovet et al (2014), for example for C i, Al i, and Ti i (Limandri et al 2012), demonstrated a good agreement with the maximum difference between the measurements and the calculations with (11) at the peak for Ti i of less than 15%.…”

Experimental determination of multiple ionization cross sections in Si by electron impact

“…It can be seen that there is a good agreement between the x-ray production cross section values obtained here and the other experimental results, particularly with those from Ref. [1]. The differences between the present data and those from [35] could be due to the fact that their results were obtained using an EDS instead of a WDS.…”

“…x-ray production cross section for single ionization. Black dots: present results; white dots: Zhu et al [35]; gray dots: Limandri et al [1] Figure 3 displays the results obtained for K-shell single ionization, along with data obtained by means of the bulk sample method [35] and through measurements performed irradiating a thin target [1]. It can be seen that there is a good agreement between the x-ray production cross section values obtained here and the other experimental results, particularly with those from Ref.…”

“…The procedure followed to determine the solid angle and the intrinsic efficiency of the EDS was explained elsewhere [1]. The solid angle obtained was (1.15 ± 0.05) × 10 −4 sr, whereas ε int was evaluated at 1.74 keV, resulting in 0.707 ± 0.007.…”

“…The experimental determination of inner-shell ionization cross sections is a matter of continuous interest in atomic physics [1][2][3][4][5][6][7][8]. As detector performances and speeds are improved, more depurated methodologies can be used to check the increasingly sophisticated and realistic theoretical models used to predict them [1,5,9]. The accurate determination of cross sections is of practical application in the field of analytical techniques like electron probe microanalysis, and it is also necessary for the simulation of the electron transport in the scope of materials science and medical physics [10].…”