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The double K-shell ionization of Sc, Cr and Cu induced by electron impact was investigated via high energy resolution measurements of the Kα diagram transitions and the transitions resulting from the radiative decay of K-shell double vacancy states, namely the Khα hypersatellites. For Sc, the Kβ diagram lines and Khβ hypersatellites were also measured. The measurements were carried out in-house with a von Hamos curved crystal spectrometer operated in the so-called direct geometry in which the anodes of Sc, Cr and Cu X-ray tubes were used as targets. For each element, the electron kinetic energy was chosen to be about twice the threshold energy for the double 1s ionization. The double-to-single ionization cross-sections ratios PKK were deduced from the hypersatellite-to-diagram line yield ratios, corrected beforehand for the self-absorption of the X-rays in the target and the energy dependent efficiency of the spectrometer. The obtained ratios are discussed and compared to other PKK values found in the literature for electrons and photons.

We report on the radiative decay of double $K$-shell vacancy states produced in solid Ca, V, Fe, and Cu targets by impact with about 10 MeV/amu C and Ne ions. The resulting $K$ hypersatellite x-ray emission spectra were measured by means of high-energy-resolution spectroscopy using a von Hamos bent crystal spectrometer. The experiment was carried out at the Philips variable energy cyclotron of the Paul Scherrer Institute. From the fits of the x-ray spectra the energies, line widths, and relative intensities of the hypersatellite x-ray lines could be determined. The fitted intensities were corrected to account for the energy-dependent solid angle of the spectrometer, effective source size, target self-absorption, crystal reflectivity, and detector efficiency. The single-to-double $K$-shell ionization cross-section ratios were deduced from the corrected relative intensities of the hypersatellites and compared to theoretical predictions from the semiclassical approximation model using hydrogenlike and Dirac-Hartree-Fock wave functions and from classical trajectory Monte Carlo calculations.

International audience; The x-ray atomic properties of nickel (Ni) were investigated in a unique approach combining different experimental techniques to obtain new, useful and reliable values of atomic fundamental parameters for x-ray spectrometric purposes and for comparison with theoretical predictions. We determined the mass attenuation coefficients in an energy range covering the L-and K-absorption edges, the K-shell fluorescence yield and the $K\beta$ / $K\alpha$ and $K\beta_{1,3}$/$K\alpha_{1,2}$ transition probability ratios. The obtained line profiles and linewidths of the $K\alpha$ and $K\beta$ transitions in Ni can be considered as the contribution of the satellite lines arising from the [KM] shake processes suggested by Deutsch et al (1995 Phys. Rev. A 51 283) and Ito et al (2016 Phys. Rev. A 94 042506). Comparison of the new data with several databases showed good agreement, but also discrepancies were found with existing tabulated values.

The potential of valence to core Al X-ray emission spectroscopy to determine aluminum distribution in ferrierite zeolites was investigated. The recorded emission spectra of four samples prepared with different structure directing agents exhibit slight variations in the position of the main emission peak and the intensity of its low energy shoulder. Theoretical calculations indicate that an increased intensity of the Kβx shoulder in the Al emission spectra can be linked to a predominant occupation of the T3 site by a single aluminum atom. This study thus suggests that valence to core X-ray emission spectroscopy can be applied to help determine the occupation of aluminum at crystallographic T-sites in zeolites.

We report on a laboratory-based facility for in-house x-ray absorption fine structure (XAFS) measurements. The device consists of a conventional x-ray source for the production of the incident polychromatic radiation and a von Hamos bent crystal spectrometer for the analysis of the incoming and transmitted radiation. The reliability of the laboratory-based setup was evaluated by comparing the Cu K-edge and Ta L3- edge XAFS spectra obtained in-house with the corresponding spectra measured at a synchrotron radiation facility. To check the accuracy of the device, the K- and L-edge energies and the attenuation coefficients below and above the edges of several 3d, 4d, and 5d elements were determined and compared with the existing experimental and theoretical data. The dependence of the XAFS spectrum shape on the oxidation state of the sample was also probed by measuring inhouse the absorption spectra of metallic Fe and two Fe oxides (Fe2O3 and Fe3O4).

The design and performance of a high-resolution transmission-type X-ray spectrometer for use in the 15-26 keV energy range at synchrotron light sources is reported. Monte Carlo X-ray-tracing simulations were performed to optimize the performance of the transmission-type spectrometer, based on the DuMond geometry, for use at the Super X-ray absorption beamline of the Swiss Light Source at the Paul Scherrer Institute. This spectrometer provides an instrumental energy resolution of 3.5 eV for X-ray emission lines around 16 keV and 12.5 eV for emission lines at 26 keV, which is comparable to the natural linewidths of the K and L X-ray transitions in the covered energy range. First experimental data are presented and compared with results of the Monte Carlo X-ray simulations.

We report on vacuum ultraviolet (VUV) excited photoluminescence (PL) spectra emitted from a chemical vapor deposited MoS2 few-layered film. The excitation spectrum was recorded by monitoring intensities of PL spectra at ~1.9 eV. A strong wide excitation band peaking at 7 eV was found in the excitation. The PL excitation band is most intensive at liquid helium temperature and completely quenched at 100 K. Through first-principles calculations of photoabsorption in MoS2, the excitation was explicated and attributed to transitions of electrons from p- and d- type states in the valence band to the d- and p-type states in the conduction band. The obtained photon-in/photon-out results clarify the excitation and emission behavior of the low dimensional MoS2 when interacting with the VUV light sources.

We report on the surface-sensitive grazing emission X-ray fluorescence technique combined with synchrotron radiation excitation and high-resolution detection to realize depth-profile measurements of Al-implanted Si wafers. The principles of grazing emission measurements as well as the benefits offered by synchrotron sources and wavelength-dispersive detection setups are presented. It is shown that the depth distribution of implanted ions can be extracted from the dependence of the X-ray fluorescence intensity on the grazing emission angle with nanometer-scale precision provided that an analytical function describing the shape of the depth distribution is assumed beforehand. If no a priori assumption is made, except a bell shaped form for the dopant distribution, the profile derived from the measured angular distribution is found to reproduce quite satisfactorily the depth distribution of the implanted ions. Copyright © 2012 John Wiley & Sons, Ltd.

The synchrotron radiation based high-resolution grazing emission X-ray fluorescence (GEXRF) technique was used to extract the distribution of Al ions implanted with a dose of 1016 atoms/cm2 in Si wafers with energies ranging between 1 and 100 keV. The depth distributions of the implanted ions were deduced from the measured angular profiles of the Al-Kα X-ray fluorescence line with nanometer-scale precision. The experimental results were compared to theoretical predictions of the depth distributions resulting from ion implantation. A good agreement between experiment and theory was found which proved that the presented high-resolution grazing emission X-ray fluorescence technique is well suited to perform depth profiling measurements of impurities located within the extinction depth, provided the overall shape of the distribution can be assumed a priori.

High-resolution measurements of the photoinduced X-ray emission of liquid mercury were performed, using a transmission DuMond-type crystal spectrometer for transitions above 11 keV and a reflection von Hamos-type crystal spectrometer for transitions below 11 keV. The target X-ray fluorescence was produced by irradiating the sample with the Bremsstrahlung from X-ray tubes. The energies and natural linewidths of 6 K-shell, 26 L-shell and 2 M-shell X-ray transitions were determined. Using a least-squares-fit method to solve the two sets of equations derived from the observed transition energies and transition widths the binding energies of the subshells K to M₅ and O₁ and the level widths of the subshells K to N₅ and O₁ could also be determined.

In this work two synchrotron radiation-based depth-sensitive X-ray fluorescence techniques, grazing incidence X-ray fluorescence (GIXRF) and grazing emission X-ray fluorescence (GEXRF), are compared and their potential for non-destructive depth-profiling applications is investigated. The depth-profiling capabilities of the two methods are illustrated for five aluminum-implanted silicon wafers all having the same implantation dose of 1016 atoms per cm2 but with different implantation energies ranging from 1 keV up to 50 keV. The work was motivated by the ongoing downscaling effort of the microelectronics industry and the resulting need for more sensitive methods for the impurity and dopant depth-profile control. The principles of GIXRF and GEXRF, both based on the refraction of X-rays at the sample surface to enhance the surface-to-bulk ratio of the detected fluorescence signal, are explained. The complementary experimental setups employed at the Physikalisch-Technische Bundesanstalt (PTB) for GIXRF and the University of Fribourg for GEXRF are presented in detail. In particular, for each technique it is shown how the dopant depth profile can be derived from the angular intensity dependence of the Al Kα fluorescence line. The results are compared to theoretical predictions and, for two samples, crosschecked with values obtained from secondary ion mass spectroscopy (SIMS) measurements. A good agreement between the different approaches is found proving that the GIXRF and GEXRF methods can be efficiently employed to extract the dopant depth distribution of ion-implanted samples with good accuracy and over a wide range of implantation energies.

We report on a high-resolution transmission-type curved crystal spectrometer based on the modified DuMond slit geometry. The spectrometer was developed at the University of Fribourg for the study of photoinduced X-ray spectra. K and L X-ray transitions with energies above about 10 keV can be measured with an instrumental resolution comparable to their natural linewidths. Construction details and operational characteristics of the spectrometer are presented. The variation of the energy resolution as a function of the focal distance and diffraction order is discussed. The high sensitivity of the spectrometer is demonstrated via the 2s-1s dipole-forbidden X- ray transition of Gd which could be observed despite its extremely low intensity. The precision of the instrument is illustrated by comparing the sum of the energies of the Au K–L 2 and L 2–M 3 cascading transitions with the energy of the crossover K–M 3 transition as well as by considering the energy differences of the Gd Kα1 X-ray line measured at five different diffraction orders. Finally, to demonstrate the versatility of the spectrometer, it is shown that the latter can also be used for in-house extended X- ray absorption fine structure measurements.

M. Czarnota,1,* D. Banaś,1 M. Berset,2 D. Chmielewska,3 J.-Cl. Dousse,2 J. Hoszowska,2 Y.-P. Maillard,2 O. Mauron,2 M. Pajek,1 M. Polasik,4 P. A. Raboud,2 J. Rzadkiewicz,5 K. Slabkowska,4 and Z. Sujkowski3,† 1Institute of Physics, Jan Kochanowski University, 25-406 Kielce, Poland 2Department of Physics, University of Fribourg, CH-1700 Fribourg, Switzerland 3Soltan Institute for Nuclear Studies, 05-400 Otwock-Świerk, Poland 4Faculty of Chemistry, Nicholas Copernicus University, 87-100 Torun, Poland 5National Centre for Nuclear Research, 05-400 Otwock-Świerk, Poland (Received 15 June 2013; published 11 November 2013)

We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV–9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

The mechanisms leading to the production of hollow K shell atoms via single photon impact were investigated for a variety of light elements with 12 ≤ Z ≤ 23. The double 1s vacancy states were produced by irradiating the samples with intense monoenergetic synchrotron radiation beams. The double-to-single K-shell photoionization probabilities PKK and the absolute double K-shell photoionization cross sections σ²⁺ were determined by measuring with a high-resolution bent von Hamos crystal spectrometer the Kαh hypersatellite X-ray emission of the samples. The measurements were performed over a wide range of incoming photon energies from threshold up to energies beyond the broad maximum of the double-to-single photoionization cross section ratios. The PKK and σ²⁺ were determined from the relative yields of the resolved Kαh hypersatellite lines. For Mg, Al and Si, the two-electron one-photon (TEOP) Kααh transitions which represent an alternative but much weaker decay channel for double 1s vacancy states could be also observed, using a highly efficient flat crystal wavelength dispersive spectrometer. This observation of single photon-induced TEOP transitions has shown that the I(Kαh)/I(Kααh) branching ratios are very poorly reproduced by most of existing theoretical models. Besides the relative yields of the hypersatellite and TEOP transitions, the energies and natural linewidths of the Kαh and Kααh X-ray lines were also determined. The energies are found to be in good agreement with different theoretical predictions, whereas the linewidths are significantly underestimated by the calculations, except if non-lifetime broadening effects such as the outer-shell ionization and the open valence configuration are taken into consideration.

The KMM radiative Auger (RA) x-ray spectra of solid Ca were induced by monochromatic synchrotron radiation and measured with a high-resolution von Hamos bent crystal spectrometer. Two excitation energies were employed, one in the near K threshold region and the second well above the K absorption edge. The KMM RA spectral structure and relative intensity with respect to the diagram K{beta}{sub 1,3} (K-M{sub 3,2}) line are found to be independent of the excitation energy. The overall RA structure resembles the density of unoccupied s, p, and d states. Due to solid-state effects, however, spectral features resulting from the major discrete shake-up transitions could not be resolved. For the total KMM RA to K{beta}{sub 1,3} yield ratio, a value of 0.053(3) is obtained. The latter is compared to theoretical predictions and available experimental data obtained by various types of target excitation.

The electron-induced ${L}_{3}M$ two-step double ionization cross sections of metallic Pd were determined experimentally for incident electron beam energies ranging from the double ionization threshold up to 18 keV. The double ${L}_{3}M$ ionization cross sections were derived from the intensity ratios (${I}_{L\ensuremath{\alpha}M}$:${I}_{L\ensuremath{\alpha}}$) of the resolved $M$ satellites to the parent diagram lines. The sample was bombarded with monoenergetic electrons from an energy-tunable 20-kV electron gun. The diagram and $M$-satellite x-ray lines were measured by means of high-resolution x-ray spectroscopy, using a reflection-type von Hamos bent crystal spectrometer. The two-step partial cross sections were determined by subtracting from the measured total double ionization cross sections the contributions due to the shake process and ${L}_{1}$-${L}_{3}{M}_{4,5}$ Coster-Kronig transitions. Despite the thick target employed in the present study, the dependence of the two-step cross sections on the incoming electron energy could be derived using a target slice decomposition method. It is shown that the obtained energy dependence can be well reproduced by the semiempirical parametrization model of Pattard and Rost.

Single-photon double $K$-shell ionization of low-$Z$ neutral atoms in the range $12\ensuremath{\leqslant}Z\ensuremath{\leqslant}23$ is investigated. The experimental method was based on measurements of the high-resolution $K\ensuremath{\alpha}{}^{h}$ hypersatellite x-ray spectra following the radiative decay of the $K$-shell double-vacancy states excited by monochromatic synchrotron radiation. The photon energy dependence of the double $K$-shell ionization was measured over a wide range of photon energies from threshold up to and beyond the maximum of the double-to-single photoionization cross section ratios. From the high-resolution x-ray emission spectra the energies and linewidths of the hypersatellite transitions, as well as the $K{\ensuremath{\alpha}}_{1}^{h}$:$K{\ensuremath{\alpha}}_{2}^{h}$ intensity ratios, were determined. The relative importance of the initial-state and final-state electron-electron interactions to the $K$-shell double photoionization is addressed. Physical mechanisms and scaling laws of the $K$-shell double photoionization are examined. A semiempirical universal scaling of the double-photoionization cross sections with the effective nuclear charge for neutral atoms in the range $2\ensuremath{\leqslant}Z\ensuremath{\leqslant}47$ is established.

An observation of the internal structure of the L-shell hypersatellite x rays resulting from the one-photon decay of L{sup -2} double-vacancy states in palladium multiply ionized by oxygen ions is reported. The Pd L{sub 3}{yields}M{sub 4,5} x-ray spectrum was measured with a von Hamos high-resolution crystal spectrometer. The complex shape of the observed spectrum could be interpreted in detail using relativistic multiconfiguration Dirac-Fock calculations. The relative intensities of the measured x rays were found to be in good agreement with semiclassical approximation calculations using relativistic Dirac-Hartree-Fock wave functions.

The multiple ionization of the L- and M-shells of Pd by fast oxygen ions has been studied by measuring with high-resolution the satellite structures of the Lα1,2 X-ray transitions. Relativistic multi-configuration Dirac-Fock (MCDF) calculations were used to interpret the complex X-ray spectrum, allowing to derive the number of L- and M-shell spectator vacancies at the moment of the X-ray emission. After correcting these numbers for the atomic vacancy rearrangement processes that take place prior to the X-ray emission, the ionization probabilities corresponding to the collision time were obtained. The latter were compared to predictions of the semiclassical approximation (SCA) and the geometrical model. The SCA calculations were performed using relativistic hydrogenic and self-consistent Dirac-Hartree-Fock (DHF) electronic wave functions. It was found that the use of the more realistic DHF wave functions in the SCA calculations leads to a much better description of the measured ionization probabilities for both the L- and M-shells.

The xenon $L$-subshell Coster-Kronig (CK) transition yields were revisited via high-resolution measurements of the $L{\ensuremath{\alpha}}_{1,2}$ (${L}_{3}\ensuremath{-}{M}_{4,5}$) and $L{\ensuremath{\beta}}_{1}$ (${L}_{2}\ensuremath{-}{M}_{4}$) x-ray emission lines. The $L$ x-ray spectra were measured employing a Johansson-type curved crystal spectrometer and energy-tunable synchrotron radiation. The CK yields were derived from the relative $L$ x-ray intensity jumps at the $L$ edges by fitting the fluorescence intensities as a function of the photon energy to the $L$-subshell photoionization cross sections. The latter were obtained from the measured $L$-edge photoabsorption spectrum. Values of $0.118\ifmmode\pm\else\textpm\fi{}0.029$, $0.383\ifmmode\pm\else\textpm\fi{}0.037$, and $0.096\ifmmode\pm\else\textpm\fi{}0.016$ were found for the ${f}_{23}$, ${f}_{13}$, and ${f}_{12}$ CK yields, respectively. Thanks to high resolution, the ${L}_{1}$ fluorescence yield of $0.059\ifmmode\pm\else\textpm\fi{}0.002$ was also determined from intensity ratios of the well-resolved $L{\ensuremath{\beta}}_{4}$ (${L}_{1}\ensuremath{-}{M}_{2}$) and $L{\ensuremath{\beta}}_{1}$ (${L}_{2}\ensuremath{-}{M}_{4}$) lines.

We demonstrate that ultralow-level Al impurities on a silicon surface can be measured by using the high-resolution grazing emission x-ray fluorescence (GEXRF) technique combined with synchrotron-radiation excitation. An Al-impurity level of about ${10}^{12}\text{ }\text{atoms}/{\text{cm}}^{2}$ was reached by observing the $\text{Al}\text{ }K\ensuremath{\alpha}$ x-ray fluorescence in the resonant Raman-scattering background-``free'' regime by choosing an appropriate beam energy below the $\text{Si}\text{ }K$ absorption edge. Present results show that by combining the GEXRF method with the vapor phase decomposition technique the ${10}^{7}\text{ }\text{atoms}/{\text{cm}}^{2}$ level can be reached for Al detection on silicon. Finally, we found that the high-resolution GEXRF technique is a sensitive tool to study the morphology of surface nanostructures.

We report on the experimental determination of the palladium L-subshell Coster-Kronig (CK) transition yields via high-resolution measurements of the L{alpha}{sub 1,2} (L{sub 3}-M{sub 4,5}) and L{beta}{sub 1} (L{sub 2}-M{sub 4}) x-ray emission lines. The L x-ray spectra were recorded by means of curved crystal spectrometers employing energy-tunable synchrotron radiation for fluorescence production. The CK yields were derived from the relative L x-ray intensity jumps at the L edges by fitting the fluorescence intensities as a function of the photon energy to the photoionization cross sections. The L x-ray intensities were corrected for solid-state effects which were estimated from the comparison of the measured and theoretical Pd L-edge x-ray-absorption spectra. Thanks to high resolution, the partial CK yield f{sub 13}{sup L{sub 1}}{sup L{sub 3}}{sup M} could be extracted from the intensities of the resolved L{alpha}M satellite transitions. For f{sub 23}, f{sub 12}, and f{sub 13} CK rates, values of 0.164{+-}0.033, 0.047{+-}0.001, and 0.730{+-}0.039 were found, respectively. For the partial CK yields f{sub 13}{sup L{sub 1}}{sup L{sub 3}}{sup M} and f{sub 13}{sup L{sub 1}}{sup L{sub 3}}{sup N}, results of 0.406{+-}0.023 and 0.324{+-}0.032, respectively, were obtained.

International audience; A twin crystal-spectrometer assembly, operated in the focusing compensated asymmetric Laue geometry has been developed for accurate spectroscopy of fast highly charged heavy ions in the hard-X-ray region. Coupled to the focusing crystal optics is a specially developed two-dimensional position-sensitive X-ray detector which is necessary for retaining spectral resolution also for fast moving sources. We summarize the crystal optics and demonstrate the usefulness of the instrument for spectroscopy of both stationary and fast moving X-ray sources. Results are reported from several tests employing a 169Yb gamma-ray source and the Lyman radiation of one-electron Pb81+ ions traveling at a velocity corresponding to [beta]†[reverse not equivalent]†v/c†[approximate]†0.59. The features of the instrument presented may be useful in many applications where it appears difficult to make the leap from conventional X-ray energy measurements to wavelength-dispersive spectroscopy based on crystal optics.

High-spin states in 162Tm and 164Tm have been studied by 152,154Sm(14N, 4n) reactions. Measurements of γ-rays, angular distributions and γγ-coincidences were performed using Ge detectors. In each isotope, two side bands are observed besides the yrast band, which are followed up to high-spin states. An interpretation of the experimental results is proposed in the framework of the cranked shell-model. Results on gyromagnetic ratios in the yrast band of a series of odd-N Tm nuclei are presented. Magnetic properties of the side bands are also discussed.

High-spin rotational states of 158,160,162,164Tm were investigated by in-beam γ-spectroscopy using the (14N, 4n) and (14N, 6n) reactions. The strongly-aligned band π[ h 11 2 ]ν[ i 13 2 ] has been observed in all these nuclei. Our experimental results, together with the data obtained by another group on 166Tm, are interpreted in the frame of a cranking-model analysis. The behaviour of the moment of inertia versus rotational frequency and the existence of a triaxial shape is discussed.

Various 3-dimensional nano-scaled periodic structures with different configurations and periods deposited on the surface of silicon and silica substrates were investigated by means of the grazing incidence and grazing emission X-ray fluorescence techniques. Apart from the characteristics which are typical for particle- and layer-like samples, the measured angular intensity profiles show additional periodicity-related features. The latter could be explained by a novel theoretical approach based on simple geometrical optics (GO) considerations. The new GO-based calculations were found to yield results in good agreement with experiment, also in cases where other theoretical approaches are not valid, e.g., periodic particle distributions with an increased surface coverage. (C) 2014 Elsevier B.V. All rights reserved.