A quantitative analysis of very light elements by the electron probe microanalyser

Abstract

A modified ZAF method was chosen. For the atomic-number correction, the classical form is maintained by using the mean ionization energy of Zeller. For the absorption correction, the use of the complete expression of the function f( chi ), including the surface ionization phi (O), is required. A few examples of quantitative analysis are given, based on this method. A new semi-empirical table of absorption coefficients, with regard to these elements, is presented. The experimental difficulties which were encountered are examined. This method does not apply to all the elements, only to the low-atomic-number ones. In fact, for each element, a particular value for sigma and h must be chosen.

Determination of Mass Attenuation Coefficients of Th, U, Np, and Pu for Oxygen KαX-Rays Using an Electron Microprobe

“…6b). Figure 7 compares our experimental MACs with the MAC values from the tabulations of Ruste & Gantois (1975), Henke et al (1982Henke et al ( , 1993, Farthing & Walker (1990), and the FFAST (Chantler et al, 2005) and PENELOPE (Sabbatucci & Salvat, 2016;Salvat, 2019) theoretical MACs. The numerical values of the MACs are listed in Table 3.…”

“…Thus, Farthing and Walker's database relies on Henke et al's tabulation for soft X-rays. It is worth also mentioning another tabulation of MACs for the ultra-light elements, which was compiled by Ruste & Gantois (1975). The latter tabulation was obtained by modifying the MAC value, in a modified ZAF program, such that systematic EPMA measurements on well-characterized oxide, carbide, nitride, and boride specimens yielded concentrations consistent with the nominal values.…”

Low-Voltage Electron-Probe Microanalysis of Uranium

“…To test the magnitude of the overlap interference, six analyses were carried out on a C-free U-metal at 10 kV, and the results were quantified both with and without the U overlap correction The P&P MAC measurement method was applied to measurements carried out in this study for O Kα and U Mα absorption in UO 2 using Casino (Drouin et al, 2007) and PENEPMA (Llovet & Salvat, 2016) Figure 11 compares these values against other published values. These range from 5,260 (Henke et al, 1993) to 14,021 cm 2 /g (Ruste & Gantois, 1975), a factor of almost three difference, demonstrating how poorly constrained this MAC value is. The CASINO-and PENEPMA-derived values from this study both compare very closely to Pöml & Llovet's (2020) experimentally derived value of 9,318 cm 2 /g.…”

ϕ(ρz) Distributions in Bulk and Thin Film Samples for EPMA. Part 1: A Modified ϕ(ρz) Distribution for Bulk Materials, Including Characteristic and Bremsstrahlung Fluorescence

“…To model the deceleration factor, Pouchou and Pichoir have used a modified version of Bethe's law for low energy electrons: where and with the index i running through the number of elements composing the studied material. J i is the mean ionization potential, in keV, as obtained by Zeller and cited by Ruste & Gantois (1975): …”