Measurements of L_α, L_βx-ray production cross sections of Pb by 16–40 keV electron impact

Abstract

The measurement of Lα, Lβ x-ray production cross sections for the element Pb (Z = 82) by 16–40 keV electron impact is reported in this paper. The target used in the experiment was prepared by evaporating the elemental Pb onto a thick pure carbon substrate. The effects of multiple scattering of electrons when penetrating the target film, of electrons reflected from the thick pure carbon substrate and of bremsstrahlung photons produced by the impact of incident electrons on the target are corrected using the Monte Carlo method. The experimental data, reported here for the first time in the energy region of interest, are compared with the plane-wave Born approximation theory with exchange, Coulomb and relativistic corrections. They are in good agreement.

Bremsstrahlung spectra produced by kilovolt electron impact on thick targets

“…The experimental setup is described in [24]. Mono-energetic electron beams up to several tens of keV were provided by an electron gun, and the beam current intensities were adjusted in accordance with characteristic X-ray counting rates.…”

Measurements of Lα, Lβ X-ray production cross sections of Bi by 17–40keV electron impact

“…At present, most of the experimental data are on the K-shells by electron impact [7][8][9]. Only seldom L-shell ionization data of Ag, Au, W, Pt, Ge, Ga, As, Sn, In, Re and Pb have been reported [8][9][10][11][12][13][14][15][16], and there are very little experimental data for M shells [9,16,17]. The reason is maybe due to the fact that the spectral lines for the measurements of L-and higher-shell ionization cross-section data are more complicated than the K-shell data and the L-and highershell ionization cross sections are responsible for not only the Auger but also the Coster-Kronig (CK) transitions [8,9].…”

“…It can be seen that for the medium-Z elements the calculation results from these theoretical models and the empirical formulae were very close each other and in good agreement with the experimental K-shell ionization cross sections, but for lower-and higher-Z elements the calculation results from these theoretical models and the empirical formulae were obviously different. For the experimental data of L-shell X-ray production cross sections, from the recently published papers we noticed that for higher-Z elements, for example, W (Z = 74), Pt (Z = 78), Au (Z = 79) [10] Au (Z = 79) [8] and Pb (Z = 82) [16], the DWBA [4][5][6] and PWBA-C-Ex theories [2,3] can describe very well the experimental L a [10] and L a , L b [8] X-ray production cross sections. However, for lower-Z elements, for example, Ga (Z = 31), As (Z = 33) [9] and Ag (Z = 47) [8], the predictions of the DWBA theory [4][5][6] and the PWBA-C-Ex theory [2,3] are similar [9] and in general $10-25% larger than the experimental data [8,9], but except for Ge (Z = 32) element where the predictions of the DWBA theory [4][5][6] were slightly smaller than the experimental data [11].…”

L shell X-ray fluorescence parameters of Pb in phthalocyanine complexes

“…These differences arise from the production cross-section values which are used to calculate the average Lshell fluorescence yields and theω 3 sub-shell fluorescence yields. L and M shell X-ray fluorescence parameters are more complicated than the K shell parameters because spectral lines of L and M shell are dependent not only on the cross sections of the various subshell but also on the Coster-Kronig transitions (Wu et al (2007), Xu (1991)) pointed out about the effect of multivacancy on the L X-ray fluorescence yields and it was concluded that both fluorescence yields and X-ray intensity ratios of multiple ionized atoms can be significantly different from those of the singly ionized atoms and vary with the number and configuration of vacancies. Multiple ionization of the atom might be a potential source of observed changes on the L X-ray fluorescence parameters.…”