It is possible to obtain the Li Kα spectrum of LiF on an electron microprobe, with minimal damage, provided a low acceleration energy (1 kV) and a small current density (1 pA/μm 2 ) are used. The presented spectrum agrees with the one obtained with synchrotron radiation many years ago and is expected to be free of damage. The spectrum displays two main peaks: the first one at c.a . 47 eV coming from the electron transition from the occupied valence states toward the Li 1s core level; the second one at c.a . 62 eV giving evidence of the radiative recombination of the lithium core exciton. These features, as well as the background due to cathodoluminescence, change drastically after 1 min of electron irradiation, due to fluorine leaving the sample and the subsequent oxidation of the remaining lithium atoms in the residual atmosphere of the microprobe.

Higher order diffraction from surface contamination poses a major challenge for soft x-ray spectral analysis using reflection zone plate spectrometers in electron probe microanalysis. We developed two correction methods applied to the Al L2,3 and Zn M2,3 emissions in AlZn60 alloy spectra: sequential overlay and subtraction of C K alpha and O K alpha reference spectra, and subtraction of O K alpha higher order contributions using an isolated peak of the sample under study. The second subtraction method provides superior correction of oxygen interferences while preserving intrinsic emission shapes. These approaches were validated on the Si L and Al L bands of the leuchtenbergite mineral.

In this work, we present the way we perform high-resolution wavelength-dispersive X-ray spectrometry in the ultra-soft X-ray range. For this purpose, we use a reflection zone plate spectrometer working, as a variable line spacing grating spectrometer, in the 40 - 110 eV spectral range. We show that the shape of the emission bands can be reproduced by simulation of spectra obtained from the local and partial density of states calculated with the density functional theory. The knowledge of the electronic structure of the material under consideration is important to properly interpret the spectra, which can be complicated when many elements are present in the sample, such as the amblygonite phosphate. We also show the first attempt of elemental quantification of an AlCuLi alloy from intensities measured with the reflection zone plate spectrometer. The obtained mass fractions are in good agreement with those obtained in a standard way from measurements performed in the soft X-ray range with crystal spectrometers.

Measurements are presented of the Si and Al L X-ray emission bands of Ni silicides (Ni31Si12 and Ni2Si) and Ni aluminides (Ni2Al3 and NiAl3). The spectra, obtained with a soft X-ray spectrometer and electron beam excitation, reflect the distribution of Si and Al s- and d-states in the valence band. The experimental spectra are compared with X-ray emission spectra calculated from the local and partial densities of states obtained with density functional theory.

We use a Zr/Si multilayer presenting a gradient of period to probe the shape of the Si L2,3 emission band (maximum around 92 eV) in and out of Bragg conditions. The sample was prepared by magnetron sputtering and its reflectance measured in the photon energy range of interest with synchrotron radiation. The study is performed on an electron microprobe equipped with a reflection zone plate spectrometer operating in the 40-120 eV photon energy range. Outside Bragg conditions, the observed spectrum is that of amorphous silicon as expected from the small thickness of the Si layers. In Bragg conditions, that is to say when the period of the multilayer, the emitted photon energy and detection angle fulfill the Bragg law, the shape and intensity of the emission band change. The main change is the intensity decrease of the shoulder present around 97 eV. Purcell-Kleppner and Kossel effects, or a combination of both, are suggested to explain the evolution of the Si L2,3 emission band when going through the Bragg conditions.

Certain radiative processes have their characteristics, such as spectrum, spatial distribution or yield, modified by the medium in which they are generated. Such media are referred to as structurally active media. This article examines some of these processes, such as fluorescence, Raman scattering and the Cerenkov effect in the X-UV range. The active media considered are periodic structures capable of producing Laue–Bragg diffraction; the phenomena involved are the Purcell–Kleppner effect, Kossel diffraction, the anomalous Lamb effect and the Bragg–Raman and Bragg–Cerenkov effects.

It is possible to obtain the Li K alpha spectrum of LiF on an electron microprobe, with minimal damage, provided a low acceleration energy (1 kV) and a small current density (1 pA/mu m2) are used. The presented spectrum agrees with the one obtained with synchrotron radiation many years ago and is expected to be free of damage. The spectrum displays two main peaks: the first one at c.a. 47 eV coming from the electron transition from the occupied valence states toward the Li 1s core level; the second one at c.a. 62 eV giving evidence of the radiative recombination of the lithium core exciton. These features, as well as the background due to cathodoluminescence, change drastically after 1 min of electron irradiation, due to fluorine leaving the sample and the subsequent oxidation of the remaining lithium atoms in the residual atmosphere of the microprobe.

A MgLi dilute alloy (6% wt. Li) has been studied by x-ray emission spectroscopy in the ultra-soft x-ray range, 40-60 eV. For this purpose, a high-resolution reflection zone plate spectrometer, working as a variable line grating spectrometer, was used on an electron probe microanalyser. With the experimental conditions, current and acceleration voltage of the incident electron beam, geometry, CCD detection, the Mg L emission band is easily observed. The Fermi edge of this band shifts toward the low photon energies with the Li content. The Li K emission band is hardly detectable despite the non-negligible lithium mass fraction in the alloy. This is explained by the reabsorption of the lithium emission by the magnesium atoms, the reabsorption effect being strong in the present geometrical conditions of the experiment.

This paper presents an X-ray reflectivity study of a Sc/SiC/Al periodic multilayer deposited via magnetron sputtering and its possible adaptation to be used as a dispersive element in the crystal spectrometers equipping scanning electron microscopes and electron probe microanalyzers. This multilayer is designed for the spectral range of 45–60 eV. The results reveal a reflectance of 40.8% at 54.1 eV for a near-normal incidence angle of 7° with a narrow bandwidth of 2.6 eV. The measured and simulated reflectivity curves are very close, suggesting that this system has smooth interfaces and low interdiffusion. Owing to the growing importance of lithium and lack of spectroscopic data, we simulate a new Sc/SiC/Al stack based on the reflectivity data and optimize it to perform spectroscopy in the range near the Li K absorption edge around 55 eV, which is in the spectral range of the Li Kα emission band. This optimization is achieved by tuning the thicknesses of the different layers and the number of periods of the multilayer using an in-house Python script. The optimization results are compared with the performances of other multilayers employed in the same energy range and at a working angle close to 30° grazing, including Be/Si/Al. This analysis indicates that the Sc/SiC/Al multilayer could be a good candidate for performing spectroscopy in the Li K range.

Implementing a newly developed spectrometer for the soft x-ray range of (35-130) eV based on reflection zone plates was successfully accomplished on an electron probe microanalyzer. In this context, we present the first spectra acquired using this setup, including those of elements such as Be (K alpha), C (K alpha), Mg (L2,3), Al (L2,3), and Si (L2,3). We have also conducted an analysis of several lithium compounds and measured the emission of Li K alpha from metallic Li, LiF, and LiNbO3. Some of the results were compared with density functional theory calculations. The spectrum obtained for the lithium-bearing mineral amblygonite Li0.75Na0.25Al(PO4)F0.75(OH)0.25 is chosen to discuss some of the challenges faced.

In the field of quantitative X-ray analysis techniques, such as electron probe microanalysis, precise knowledge of fundamental parameters is crucial. Especially, the accurate determination of photon mass attenuation coefficients is essential to perform correct elemental quantification. While the widely used databases offer agreement for the hard X-ray range, significant differences arise for lower photon energies. Furthermore, addressing the uncertainties of the tabulated data, which can be of several hundreds of percent, is of urgent need. Driven by recent advances in analytical techniques in the low energy range including investigation of materials containing lithium, the interest in a reliable set of photon mass attenuation coefficients is steadily increasing. In this study, we experimentally determine photon mass attenuation coefficients for lithium fluoride, aluminium, and different transition metals in the extreme low energy range from 40 eV to a several hundreds of eV. This high-precision experimental determination allows a comparison with the existing data tables. We observe differences that turn out to be significant, especially around the absorption edges.

Les structures de Bragg artificielles (SBA) étudiées dans cet ouvrage ont révolutionné l’optique des rayons X. Elles reposent sur des empilements (quasi) périodiques de couches minces à l’échelle nanométrique avec des périodes voisines de la longueur d’onde du rayonnement.Rayonnement X et structures de Bragg artificielles présente les prolégomènes historiques relatifs aux sources de rayons X et au développement initial des SBA. Il analyse la modélisation des caractéristiques et des performances des SBA et leur optimisation. Les méthodes matricielles et récursives, la théorie des ondes couplées et la théorie de la diffusion sont exposées. Cet ouvrage étudie également les SBA comme sièges de phénomènes particuliers, quantiques, magnétooptiques. Il traite de l’application des SBA ainsi que des développements prometteurs de la lithographie EUV et de la réalisation de nouvelles sources de rayonnement X. Enfin, il présente les perspectives offertes dans un futur proche par les SBA, en particulier dans le domaine des sources cohérentes et du laser X.