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Kα,β X-ray lines from photon excitation were measured in selected elements from Mg to Cu using a high-resolution double-crystal X-ray spectrometer with a proportional counter, and the Kβ/Kα intensity ratio for each element was obtained, after correcting for self-absorption, detection efficiency, and crystal reflectance. This intensity ratio increases rapidly from Mg to Ca but, in the 3d elements region, the increase becomes slower. This is related to the intensity of the Kβ line involving valence electrons. The slow increase of this ratio in the 3d elements region is thought to be due to the correlation between 3d and 4s electrons. Moreover, the chemical shifts, FWHM, asymmetry indices, and Kβ/Kα intensity ratios of the Cr compounds, due to different valences, were also investigated using the same double-crystal X-ray spectrometer. The chemical effects were clearly observed, and the Kβ/Kα intensity ratio was found to be compound-dependent for Cr.

A novel approach for isomer depletion in ion-atom collisions is proposed and considered theoretically. Analyses are performed for the depletion of the ^{93m}Mo isomer for which an unexpectedly large probability was measured in the beam-based experiment of Chiara et al. [Nature (London) 554, 216 (2018)NATUAS0028-083610.1038/nature25483]. The subsequent attempt at a theoretical description based on state-of-the-art atomic theory did not reproduce the experimental result [Wu et al., Phys. Rev. Lett. 122, 212501 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.212501] and showed a dramatic disagreement with the experiment (by many orders of magnitude). This conflict calls for further research on the nature of isomer depletion mechanisms occurring in atomic processes. Here, we propose to consider the ^{93m}Mo isomer depletion as the nuclear excitation by electron capture in resonant transfer process taking into account the momentum distribution of the target electrons. Although our results only slightly shift the upper theoretical limit for the total ^{93m}Mo isomer depletion probability toward the experimental value, they show the importance of considering the Compton profile in the theoretical description, in particular for the L shell, for which the depletion probability increases by many orders of magnitude.

In order to allow the advanced interpretation of the X-ray spectra registered by the high-resolution crystal KX1 spectrometer on the JET with an ITER-like wall, especially to determine how the relative emission contributions of tungsten and molybdenum ions change during a JET discharge, the X-ray spectra have been carefully modeled over a narrow wavelength range. The simulations have been done in the framework of Collisional–Radiative model implemented in Flexible Atomic Code for an electron density (ne = 2.5 × 1019 m−3), and electron temperatures between Te = 3.0 keV and Te = 4.5 keV, typical for JET. Moreover, performed detailed analysis in the framework of the proposed procedure can be useful in determining temperature of a high temperature plasma generated in tokamaks.

On modest ionization, the change in the photon energies of characteristic K- and L-lines from high-Z (Z ∼ 75 ) ions can be used as an ionization diagnostic (Slabkowska et al., 2014). Indeed, the line shape of the L β 2 line in a spatially resolved but time-averaged L-shell spectrum from a tungsten Plasma Filled Rod Pinch plasma suggested ionization states up to +28W. Here the L β 2 line is measured with nanosecond time resolution to determine the plasma’s ionization as it varies in time. Together with the plasma temperature from the black-body radiation and the pressure from the expansion history, such a measurement could eventually determine the plasma’s equation of state.

We propose a new advanced approach to determine the parameters for plasma generated in tokamaks. It is based on a detailed interpretation of the high-resolution X-ray spectra structure for tungsten from Zn-like to Co-like and molybdenum Ne-like ions that can, and have, be registered by the KX1 crystal spectrometer on the JET tokamak with an ITER-like wall. An earlier paper found that high-resolution M X-ray spectra structures of tungsten ions can be properly interpreted only by including separately all the individual contributions from the 4s1, 4p1, 4d1 and 4f1 subshell states for the 4d → 3p transitions in the case of Cu-like (W45+) ions, and also separately both 4s → 3p and 4d → 3p transitions for the Co-like (W47+) ions. Here a similarly detailed analysis is done for the M X-ray line structures coming from Cu-like and Co-like tungsten ions and L X-ray line from Ne-like molybdenum ions in different high-temperature plasmas. The predictions are obtained within the Collisional-Radiative approach by the Flexible Atomic Code package, for plasma electron temperatures from 2.0 keV to 6.0 keV and a single electron density, 3 × 1019 m−3, that is relevant to JET. The obtained shapes of spectra for Cu- and Co-like tungsten and Ne-like molybdenum ions (benchmarks) are important part of prepared reference base, which is crucial for applications of proposed approach. These results should be also useful for ITER, and for tokamaks such as WEST and ASDEX Upgrade, where tungsten plasma-facing components are implemented and kept track of with a high-resolution X-ray diagnostic similar to those based on the KX1 spectrometer.

This paper shows the theoretical predictions of the outer-shell ionization effect on the positions of Kα1,2, Kβ1,3, and K β2 X-ray lines for some 4d-transition metals (molybdenum and palladium) and 4f rare-earth elements (dysprosium and ytterbium). The ionization energy shifts have been evaluated using the multiconfiguration Dirac-Fock method, containing Breit interaction and quantum electrodynamic (QED) corrections. The presented results are important for obtaining the information about some parameters of plasma generated by different sources, especially by pulsed power machine and short-pulse lasers.

The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This 'internal conversion' has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process-nuclear excitation by electron capture (NEEC)-a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of 'isomer depletion', which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.

This work was also supported by the National Science Centre , Poland under grant number 2017/25/B/ST2/00901. We combined different experimental techniques with a theoretical approach to determine a consistent set of diagram lines energies and binding energies. We propose an original approach consisting in determining the mass attenuation coefficients in an energy range covering the L-, M- and N- absorption edges, including a detailed evaluation of the associated uncertainties, to derive precisely the binding energies. We investigated the Lα, Lβ and M spectra of Gd with an independantly calibrated high-resolution anti-parallel double-crystal x-ray spectrometer. All the lines were identified and found in excellent agreement with the binding energies previously derived. Morever, we identified for the first time M5−O2, M4−O2,3 and M4−N2,3 diagram lines. authorsversion published

Following the first experimental observation of $^{93m}\mathrm{Mo}$ isomer depletion via nuclear excitation by electron capture (NEEC), we consider another experimental scenario related to the $^{242m}\mathrm{Am}$ isomer for which the probability of the NEEC process is expected to be even higher than for the $^{93m}\mathrm{Mo}$ isomer. The optimum experimental conditions for the production and depletion of the $^{242m}\mathrm{Am}$ isomer in a beam-based scenario are discussed. The relevant beam-target reaction cross sections have been calculated striving to ensure effective production of the $^{242m}\mathrm{Am}$ isomer. Kinetic energies required for the NEEC process to occur have been predicted for the $n=5$, 6, and 7 subshells of $^{242m}\mathrm{Am}$ ions and combined with available ion charge states at subsequent stages of the ion stopping process. The NEEC resonance strengths have been estimated for the partial contributions of individual subshells to the whole NEEC process.

The shapes and positions of the K α 1 and K α 2 x-ray lines for 3d-transition metals can vary substantially as electrons are stripped from the outer-shells. This paper shows the detailed line shapes for nickel and zinc, obtained by calculations with a multiconfiguration Dirac–Fock method that includes Breit interaction and quantum electrodynamics corrections. The line shapes can be useful in interpreting hot, dense plasmas with energetic electrons for which the K x-ray lines are optically thin, as may be produced by pulsed power machines such as the plasma-filled rod pinch diode or the plasma focus, or in short-pulsed high power laser plasmas.

The $K\ensuremath{\beta}$ x-ray spectra of the elements from Ca to Ge have been systematically investigated using a high-resolution antiparallel double-crystal x-ray spectrometer. Each $K{\ensuremath{\beta}}_{1,3}$ natural linewidth has been corrected using the instrumental function of this type of x-ray spectrometer, and the spin doublet energies have been obtained from the peak position values in $K{\ensuremath{\beta}}_{1,3}$ x-ray spectra. For all studied elements the corrected $K{\ensuremath{\beta}}_{1}$ x-ray lines FWHM increase linearly as a function of $Z$. However, for $K{\ensuremath{\beta}}_{3}$ x-ray lines this dependence is generally not linear in the case of $3d$ elements but increases from Sc to Co elements. It has been found that the contributions of satellite lines are considered to be $[KM]$ shake processes. Our theoretically predicted synthetic spectra of Ca, Mn, Cu, and Zn are in very good agreement with our high-resolution measurements, except in the case of Mn, due to the open-shell valence configuration effect (more than 7000 transitions for diagram lines and more than $100\phantom{\rule{0.16em}{0ex}}000$ transitions for satellite lines) and the influence of the complicated structure of the metallic Mn.

Ionization affects the energy and shape of the characteristic X-ray lines that may be excited by energetic electrons in a partially ionized plasma. We present the first theoretical predictions for copper K-line spectra in different ionization states, one of a systematic series of computations on how ionization affects inner-shell X-ray lines. Detailed computations such as these may make it possible to use individual hard X-rays lines as diagnostics for warm, dense plasmas when high-resolution X-ray spectra are available.

The origin of the complex structure of $L{\ensuremath{\gamma}}_{1}$ $({L}_{2}{N}_{4})$, $L{\ensuremath{\gamma}}_{2}$ $({L}_{1}{N}_{2})$, $L{\ensuremath{\gamma}}_{3}$ $({L}_{1}{N}_{3})$, and $L{\ensuremath{\gamma}}_{6}$ $({L}_{2}{O}_{4})$ x-ray lines of thorium in high-resolution spectra induced by oxygen projectiles has so far resisted reliable quantitative interpretation. Therefore, the detailed structure predictions for satellite (additional holes in $M,N,O$, and/or $P$ shells) and hypersatellite (additional hole in $L$ shell) $L\ensuremath{\gamma}$ x-ray lines of thorium being the results of extensive multiconfiguration Dirac-Fock calculations have been performed. Our predictions reproduce with the excellent precision the positions and shapes of characteristic parts of above high-resolution $L\ensuremath{\gamma}$ x-ray spectrum of thorium what indicates that our study has been carried out with very high accuracy. The results of this study are the precursor for proper quantitative interpretation of the complex origin of $L{\ensuremath{\gamma}}_{1},L{\ensuremath{\gamma}}_{2},L{\ensuremath{\gamma}}_{3}$, and $L{\ensuremath{\gamma}}_{6}$ lines in high-resolution x-ray spectra of thorium induced by different light and heavy projectiles.

We present here a comprehensive analysis to understand the optimal atomic conditions for the first experimental observation of nuclear excitation by electron capture (NEEC) for the 6.85 h $^{93m}\mathrm{Mo}$ isomer with spin parity $21/{2}^{+}$. The NEEC process would provide an excitation from the long-lived isomer to a depletion level with spin parity $17/{2}^{+}$, which lies only 4.85 keV higher in energy, and is itself a shorter-lived isomer that subsequently decays, releasing a substantial amount of stored energy (2429.8 keV). The depletion level decays to a $13/{2}^{+}$ state through a 267.9-keV transition that offers the opportunity for identification of NEEC because it does not occur in the natural decay of the long-lived isomer. It has been shown that, for the proposed approach, high-precision atomic predictions are essential to understanding the proper physical conditions under which the experimental observation of the NEEC process will be possible using a beam-based scenario.

Ionization of an atom's outer shells affects the energy of K-shell photons. For atoms with Z > 40, i.e. Zr and higher, such as Mo and Ag, as used in recent high-current Z-pinches at Sandia, computations with a multi-configuration Dirac-Fock method show that the K-shell photon energy increases linearly with ionization of the particular shells farther out. The linear dependence is a convenient way to estimate the plasma's ionization.

For molybdenum wire implosions on the Z-machine at Sandia National Laboratories the high-resolution measurements of x-ray spectra have been recently published. The K and L x-ray spectra modeled here within the framework of Collisional-Radiative Model using the Flexible Atomic Code package reproduce well the published data to show that such model is a reasonable one.

A recent measurement [1] demonstrates that iridium's Kα2-line, centered at ≃63286.96 eV for a cold atom, increases ≃+10 eV in energy when it is emitted by a modestly (∼17×) ionized plasma. This measurement, enabled by a near-coincident lutetium K-edge filter, agrees well with atomic physics computations. Not understood at the time was a similar measurement with a thulium filter at the ≃59370 eV energy of ytterbium's Kβ1 line, which indicated that its photon energy decreases with ionization. The computation reported here shows that the ionization energy shift for Yb's Kβ lines is indeed negative and agrees qualitatively with the measurements. For the K-lines the ionization energy shift may be most interesting in atomic physics, while for the L-lines the ionization energy shift is a promising plasma diagnostic [2] .

Spectra of the W L transitions in the energy range 8e12 keV from warm dense plasmas generated by theNaval Research Laboratory’s Gamble II pulsed power machine were recorded bya newly developed high-resolution transmission-crystal X-ray spectrometer with 2 eV accuracy. The discharges have up to 2 MVvoltage, 0.5 MA current, and produce up to 2.4 MJ/cm 3 energy density. The plasma-filled rod pinch(PFRP) diode produces a plasma with N e z 10 22 cm 3 and T e z 50 eV during the time of maximum X-rayemission. By analyzing the line shapes, it was determined that the L b 2 inner-shell transition from the4d 5/2 level was shifted to higher energy by up to 23 eV relative to nearby L b transitions from n ¼ 3 levels.In addition, the L b 2 transition was significantly broader and asymmetric compared to the n ¼ 3 transi-tions. The energy shift of the L b 2 transition results from the ionization of electrons outside the 4d shellthat perturbs the transition energies in the ions to higher values. The increased line width and asym-metry result from unresolved transitions from a range of ionization states up to þ28. The ionizationdistribution was determined by comparison of the measured energy shifts and widths to calculatedtransition energies in W ions, and the ionization was correlated with Gamble discharge parameters suchas the anode type and the high voltage delay time. This work demonstrates a new hard X-ray spectro-scopic diagnostic technique for the direct measurement of the ionization distribution in warm denseplasmas of the heavy elements W through U that is independent of the other plasma parameters anddoes not require interpretation by hydrodynamic, atomic kinetics, and radiative simulation codes. 2013 Elsevier B.V. All rights reserved.

We have investigated systematically the $K\ensuremath{\alpha}$ x-ray spectra in elements from Ca to Ge within Berger's two-Lorentzian functions model, using a high-resolution antiparallel double-crystal x-ray spectrometer, in order to obtain in detail the physical meaning of the asymmetry in the spectral profiles. The overall tendency of the corrected full width at half maximum of the $K{\ensuremath{\alpha}}_{1}$ and $K{\ensuremath{\alpha}}_{2}$ lines as a function of $Z$, as well as the linewidths, are in good agreement with the data reported in the literature. It is found, from both the experiments and calculation, that satellite lines arising from shake-off appear between the $K{\ensuremath{\alpha}}_{1}$ and $K{\ensuremath{\alpha}}_{2}$ lines. The asymmetry index of $K{\ensuremath{\alpha}}_{1}$ in $3d$ elements from Sc to Zn is ascribed to the existence of a $3d$ spectator hole. Moreover, the observed Sc $K{\ensuremath{\alpha}}_{1}$ line shows a symmetric profile unlike the Ti $K{\ensuremath{\alpha}}_{1}$ line profile, this discrepancy being explained by the existence of satellite lines on both sides of the Sc profile. Our experimental results yielded around 25% probability for the probability of shake processes creating a second hole in the $3p$ or $3d$ subshells in Sc and around 18% probability for creating a second hole the in the $3p$ in Ca. For the latter process our calculated value, using multiconfiguration Dirac-Fock wave functions and the sudden approximation yielded a 10% probability.

In the future International Thermonuclear Experimental Reactor (ITER), the interaction between the plasma and the tungsten chosen as the plasma-facing wall material imposes that the hot central plasma loses energy by X-ray emission from tungsten ions. On the other hand, the registered X-ray spectra provide alternative diagnostics of the plasma itself. Highly ionized tungsten emits extremely complex X-ray spectra that can be understood only after exhaustive theoretical studies. The detailed analyses will be useful for proper interpretation of soft X-ray plasma radiation expected to be registered on ITER-like machines, that is, Tungsten (W) Environment in Steady-state Tokamak (WEST). The simulations of the soft X-ray spectra structures for tungsten ions have been performed using the flexible atomic code (FAC) package within the framework of collisional-radiative (CR) model approach for electron temperatures and densities relevant to WEST tokamak.

The Kα X-ray emission spectra of the low-density SiO2 aerogel target bombarded by 48Ca ions with initial energy of 11.4 MeV/u were measured with a high spectral and spatial resolution along 80% of the ion beam stopping path. The Si KαL0 diagram and KαLn (up to n = 5) X-ray satellite lines corresponding to the radiative decays of atomic states with one hole in the K-shell and n-holes in the L-shell were measured. Energy shifts of the KαLn satellites with respect to their diagram Kα lines were determined and compared with the results of multiconfiguration Dirac–Fock (MCDF) calculations. The experimental energy shifts are smaller than values obtained from free-ion MCDF theory assuming an empty M-shell. The influence of the valence M-shell configuration on the satellite X-ray spectra is discussed.

Detailed multicon.guration Dirac-Fock calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on zirconium to elucidate the structure of various M-, N-shell satellite and L-shell hypersatellite L?1,2 (L3M4,5) and L?1(L2M4) lines in its X-ray spectra. For each type of lines two theoretical spectra have been synthesized: one being a sum of the Lorentzian natural line shapes and the other one being a convolution of the sum of the Lorentzian natural line shapes with the Gaussian instrumental response. The results are very helpful in reliable interpretation of various high-resolution L-X-ray spectra of zirconium target bombarded by different light and heavy projectiles.

Simulations of the shapes of Pb K x-ray spectra have been performed for an experimental situation in which single and double L- and M-shell ionization (apart from the single K-shell ionization) of target atoms occurs. The simulations are based on the results of the calculations of the energies and probabilities of various Pb K x-ray transitions, done with the multiconfiguration Dirac-Fock (MCDF) method with the inclusion of the transverse (Breit) interaction and quantum electro dynamic (QED) corrections. It has been found that most contributions to the simulated spectra considerably overlap other contributions. Thus, their extraction from the measured spectra, which provides data about the L- and M-shell ionization probability in a collision process, will only be possible using the results of theoretical studies. Our studies can be crucial in both analysis of a number of observed Pb K x-ray spectra and in designing new experiments concerning the K x-ray spectra of multiply ionized heavy atoms induced in collisions with various light or heavy projectiles of different energies.

Very extensive multiconfiguration Dirac–Fock calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on thorium to elucidate the structure of various satellite (additional vacancies in N and/or O shells) and hypersatellite (additional vacancies in M or M and N shells) M α 1 , 2 ( M 5 N 6 , 7 ) and M β 1 ( M 4 N 6 ) lines in its X-ray spectra. For each type of lines two theoretical spectra have been synthesized: one being a sum of the Lorentzian natural line shapes and the other one being a convolution of the sum of the Lorentzian natural line shapes with the Gaussian instrumental response. The obtained theoretical results will be very helpful in reliable and quantitative interpretation of various experimental M-X-ray spectra of thorium target bombarded by different light and heavy projectiles (such as O and Ne ions).

Extensive multiconfiguration Dirac–Fock calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on palladium to elucidate the structure of various satellite (additional vacancies in M and/or N shells) and hypersatellite (additional vacancies in L or L and M shells) L α 1 , 2 ( L 3 M 4 , 5 ) and L β 1 ( L 2 M 4 ) lines in its X-ray spectra. For each type of lines two theoretical spectra have been synthesized: one being a sum of the Lorentzian natural line shapes and the other one being a convolution of the sum of the Lorentzian natural line shapes with the Gaussian instrumental response. The obtained results will be absolutely essential to carry out quantitative interpretation of very complicated structure of L α 1 , 2 and L β 1 satellite and hypersatellite lines in various high-resolution L-X-ray spectra of palladium target bombarded by different light and heavy projectiles.

Predictions about the shapes of the K x-ray spectra of medium-Z and heavy atoms have been made on the basis of the results of theoretical multiconfiguration Dirac–Fock calculations (with the inclusion of the transverse Breit interaction and QED corrections) for various KL0M1 x-ray satellite lines of Pd, Tb, Ta and Th. The construction of theoretical stick and synthesized (the sum of the Lorentzian natural line shapes) K x-ray spectra (including also diagram and KL1M0 satellite lines) has enabled foreseeing such details of experimental spectra as the overlapping and visibility of particular groups of lines. The energy regions possibly best for the extraction of the satellite contributions in the measured K x-ray spectra have been indicated for each studied element. The effect of additional single ionization of the different subshells of the M shell on the structure and shapes of the spectra of various K x-ray lines has been investigated in detail for Pd, Tb, Ta and Th. It has been found that in the KL0M1 satellite spectra the shapes of the bands mainly resemble the shapes of the corresponding K x-ray diagram lines (but they are wider than the latter). For each element, the biggest average energy shifts with respect to the diagram lines are observed for a given kind of the KL0M1 lines mostly in the case of removing a 3p electron in the initial state, whereas the smallest shifts are caused by removing a 3d electron. Our study can enable the correct quantitative interpretation of the K x-ray spectra of different multiply ionized medium-Z and heavy atoms (induced in collisions with light or heavy ions) and can be instrumental in planning various new experiments involving the determination of the M- and L-shell ionization probability.

For Tb and Ta we have performed multiconfiguration Dirac–Fock calculations with the inclusion of the transverse (Breit) interaction and QED corrections, obtaining the positions and intensities of various electric dipole, electric quadrupole and magnetic dipole K X-ray diagram lines and of their KL 1 satellites. We have analyzed the effect of additional L-shell ionization on the structure and shapes of Tb and Ta K X-ray spectra on the basis of theoretically constructed stick and synthesized spectra. By comparing the theoretical spectra of Tb and Ta we have found that generally the structure and shapes of particular satellite line groups are similar for the two elements but in the case of Ta the shapes seem to be smoother than for Tb. Our study can be helpful in reliable quantitative interpretation of the K X-ray spectra of heavy elements induced during collisions with various light or heavy projectiles.

Extensive single-configuration Dirac–Fock (DF) calculations (within the multiconfiguration DF method) with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on Mo and Pd to elucidate the structure of the Kβ2L0Mr satellite lines in their X-ray spectra. For each type of lines two theoretical spectra have been synthesized: one being a sum of the Lorentzian natural line shapes and the other one being a convolution of the sum of the Lorentzian natural line shapes with the Gaussian instrumental response. The obtained results can be used to determine the M-shell ionization probability in collisions via the theoretical analysis of Kβ2 spectra of Mo and Pd induced by different energetic light and heavy ions.

Three semi-classical approaches to the simulation of ion–atom scattering: the Kirschbaum–Wilets, the Cohen energy-bounded, and the wave-packet – are used to calculate the ionization and charge-transfer cross sections for the scattering of fully stripped sulfur ions on atomic hydrogen. Their comparison in the high-energy regime is provided. Elements of microscopic analysis of Kirschbaum–Wilets trajectories are given.

The effect of the projectile K X-rays line shifts with respect to the corresponding diagram lines has been used for evaluation of a mean equilibrium charge, q ¯ , for sulphur ions passing with energies of 9.6, 16.0, 22.4 and 32.0 MeV through Al, Ti and Fe foils. The q ¯ values for sulphur ions passing through Al and reference C foils are approximately equal for the all discussed energies. In the case of Ti and Fe foils the q ¯ values are greater for the smallest energy and the difference between q ¯ values in these two groups of targets is decreasing with increasing sulphur ion energy. For sulphur ions with energy of 32.0 MeV there is no difference in q ¯ values in all targets.

Multiconfiguration Dirac–Fock calculations (with the inclusion of the transverse Breit interaction and QED corrections) have been performed for various Pb K x-ray lines. The calculated positions and intensities of many electric dipole, electric quadrupole and magnetic dipole KL0M1 and KL1M0 x-ray satellite lines have been analysed. On the basis of theoretically constructed stick and synthesized (the sum of the Lorentzian natural line shapes) K x-ray spectra, the effect of the additional single ionization of different subshells of the M shell on the shapes and structure of Pb K x-ray spectra has been investigated and compared with the effect of the single L-shell ionization. It has been found that in the KL0M1 satellite spectra the sticks are less scattered and the shapes of the bands are narrower and smoother than in the KL1M0 spectra. The much weaker influence of an additional M-shell hole on the K x-ray spectra than of an L-shell hole is also reflected in very small values of the energy shifts (with respect to the corresponding diagram lines) of the KL0M1 satellite lines in comparison with those of the KL1M0 lines. This study provides an exhaustive set of data, enabling not only the correct quantitative analysis of many experimental Pb K x-ray spectra (induced in collisions with various projectiles), but also predictions concerning the K x-ray spectra of multiply ionized Pb or other heavy atoms, which can be helpful in designing new experiments.

The high-resolution spectra of thorium Mα 1,2 (M 5 N 6,7 ) and Mβ(M 4 N 6 ) X-ray lines induced by O and Ne ions with energies 376 and 178 MeV, respectively, have been measured using a von Hamos crystal spectrometer. The measured spectra exhibit the pronounced X-ray satellite structure due to the multiple ionization in the N- and M-shells. In particular the N-shell satellites are well resolved and the M-shell hypersatellites are clearly observed, to the best of our knowledge, for the first time. The observed M-X-ray diagram transitions and their satellites are interpreted using the multi-configuration Dirac-Fock (MCDF) calculations performed for the multi-vacancy configurations including up to two spectator vacancies. The comparison shows that calculations for more vacancies are needed to reproduce the measured X-ray structure. On the other hand, the data are well interpreted qualitatively using a simplified model of the “average” MCDF satellites having binomially distributed intensities. Further MCDF calculations are in the progress, which ultimately allow to extract precise (∼0.5 eV) information on the electronic structure of the multiple ionized thorium.

Extensive single-configuration Dirac–Fock (DF) calculations (within the multiconfiguration DF method) have been performed for sulphur to explain the influence of removing electrons from L and M shells on the shapes and parameters (the average Kα and Kβ transition energies and the values of Kβ/Kα intensity ratio) of its K X-ray spectra. For Kα and Kβ diagram lines and each type of L- and M-satellite lines, the theoretical stick spectra (line positions with their relative intensities) have been presented. The theoretical results obtained can be used for interpreting the measured shapes and parameters of the K X-ray spectra of highly ionized swift sulphur projectiles passing through various foils. They can also be very helpful in interpreting various sulphur target K X-ray spectra induced by photons and different projectiles recorded by high-resolution crystal spectrometer or lower-resolution detector.

The satellite and hypersatellite K X-ray lines emitted by sulphur projectiles (with energies 9.6, 16.0, 22.4, 32.0, 65, 79, 99 and 122 MeV) passing through carbon foils (with different thickness varying from 15 to 210 μg/cm2) have been measured using a Si(Li) detector. We use a theoretical model based on the single-configuration Dirac–Fock calculations and equilibrium charge state distribution to interpret the experimental K X-ray spectra parameters. For all projectile energies, we evaluate the probability of K-hole creation, the average population of L-shell, and the average population of the 3p and 4p subshells. In the case of 9.6–32.0 MeV beam energy we evaluate also the population of L and M shells of sulphur projectiles. For the energy range 65–122 MeV, we estimate the probability of appearance of the most important configurations. The lifetimes of the studied states is also deduced.

The Kβ spectrum of 42Mo bombarded by 20.8 MeV/amu carbon ions was measured with high-resolution using a transmission-type bent crystal spectrometer operated in the modified DuMond slit geometry. The M-shell satellites of the Kβ2 transition could be well resolved, whereas for the Kβ1,3 transitions only a broadening and shift of the line centroid was observed. The composite structure of the satellite lines which consist of many components that vary in energy and strength was analyzed using theoretical energies and relative intensities obtained from multiconfiguration Dirac–Fock calculations. From the data analysis average M-shell satellite-to-diagram line yield ratios were deduced for both the Kβ1,3 and Kβ2 transitions. For the Kβ2 transition for which the relative contributions of the 3s,p and 3d spectator vacancies to the observed Kβ2M1 satellite yield could be determined, separated X(Kβ2M11,2,3):X(Kβ2M0) and X(Kβ2M14,5):X(Kβ2M0) yield ratios could even be extracted.

Kβ-to-Kα X-ray intensity ratios of Ti, Cr, Fe and Co in pure metals and in Cr0.26Fe0.74, Cr0.80Co0.20 and Ti0.80Cr0.20 alloys have been measured following excitation by 59.54 keV γ-rays from a 7400 MBq (200 mCi) 241 Am point-source. The valence electronic structure of Ti, Cr, Fe and Co in the samples have been evaluated by the comparison of the measured Kβ-to-Kα intensity ratios with the results of multiconfiguration Dirac–Fock calculations performed for various electronic configurations of these metals. The 3d-electron populations obtained for pure metallic Ti, Cr, Fe and Co agree well with the results of band structure calculations of Papaconstantopoulos (Handbook of band structure of elemental solids, Plenum Press, New York, 1986). Our analysis indicates significant increase of 3d-electron population of Ti, Cr and Fe in the alloys with respect to the pure metals, except for Cr in Cr0.26Fe0.74 where the absolute 3d-electron population of Cr is found to be slightly less as compared to that of pure Cr. It has been found that to reliably explain the observed changes in the valence electronic structure of Ti, Cr, Fe and Co in their alloys it is necessary to take into account the rearrangement of electrons between 3d and (4s,4p) states of individual metal atoms, while the transfer of 3d electrons from one element to the other element can be neglected.

Kβ-to-Kα X-ray intensity ratios of Fe and Ni in pure metals and in FexNi1−x alloys (x=0.20, 0.50, 0.58) exhibiting similar crystalline structure have been measured following excitation by 59.54 keV γ-rays from a 241Am point source, to understand as to why the properties of permalloy Fe0.2Ni0.8 is distinct from other alloy compositions. It is observed that the valence electronic structure of Fe0.2Ni0.8 alloy is totally different from other alloys which may be attributed to its special magnetic properties.

Ultrafast molybdenum wire implosions on the Z machine at Sandia produce intense pulses of multi-keV x-rays from partially ionized plasmas. The most intense radiation comes from a hot, dense core of thermal plasma in ionization equilibrium with Mo ionized to within the L-shell. Non-thermal, energetic electrons in the plasma generate Kα and Kβ radiation, whose energy is affected by Mo’s ionization state, and therefore on the plasma temperature. Based on an extensive series of recent computations on this effect, we recalculate the pinch’ Mo x-ray spectrum, with reasonable results.

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)

Kβ-to-Kα X-ray intensity ratios of Fe and Ni in pure metals and in FexNi1−x alloys for different compositions x (x=0.20, 0.50, 0.58) have been measured following excitation by 59.54 keV γ-rays from a 200 mCi 241Am point-source. For certain alloy compositions the Kβ-to-Kα intensity ratios of Fe and Ni differ considerably from those obtained for the pure metals. The 3d electron populations of Fe and Ni have been estimated by comparing the measured Kβ-to-Kα ratios with the results of multi-configuration Dirac–Fock (MCDF) calculations. Our results for the 3d electron populations of solid iron and nickel agree reasonably well with the earlier results of band structure calculations. In the case of alloys significant changes in the 3d electron population of Fe and Ni are observed for certain alloy compositions. These changes can be explained by assuming rearrangement of electrons between 3d and (4s,4p) valence band states of the individual metal atoms. For the alloy composition x=0.2 the change in the 3d electron population of Ni is the largest and has the opposite direction than in the case of other two alloy compositions. The totally different valence electronic structure of Fe0.2Ni0.8 alloy seems to explain the special magnetic properties of this alloy.

Kβ-to-Kα x-ray intensity ratios of Cr, Mn and Co have been measured in pure metals and in CrSe, MnSe, MnS and CoS compounds following excitation by 59.54 keV γ-rays from a 200 mCi 241 Am point-source. Comparison of the measured Kβ-to-Kα intensity ratios with the results of multiconfiguration Dirac–Fock (MCDF) calculations indicates a significant increase of the 3d electron population (in relation to the pure metals) for Cr in CrSe (by 1.0 ± 0.3) and for Mn in MnS (by 0.9 ± 0.3). Our Kβ-to-Kα intensity ratio for Co in CoS does not show any significant change of 3d electron population. The only observed increase of the Kβ-to-Kα intensity ratio for Mn in MnSe indicates the decrease of the number of 3d electrons by 0.6 ± 0.3. To explain evaluated changes of the 3d electron population for all the compounds, one can consider either rearrangement of electrons between 3d and 4s states of the metal or transfer of electrons from the 3d state of the metal to the ligand atom or vice versa. Although the sulphide compounds (MnS, CoS) show similar behaviour, the selenide compounds (CrSe, MnSe) show opposite behaviour which may be attributed to anomalous behaviour of rearrangement of electrons between the valence states of Cr as it happens in the case of free atom. The d–p hybridization effect which was not taken into account in our model theoretical calculation may be partly responsible for the increased Kβ-to-Kα ratio of Mn in MnSe and a comparison of the results for MnS and MnSe suggests that the nature of covalent bonding in MnSe is stronger than that of MnS.

High-resolution measurements of the Kα 1,2 X-ray spectra were performed with a bent crystal diffraction spectrometer for zirconium, niobium, molybdenum and palladium targets bombarded by 280 and 360 MeV oxygen ions. The energy differences between the Kα 1,2 diagram and the K h α 1,2 hypersatellite transitions as well as the intensity ratios I ( K h α 1 )/ I ( K h α 2 ) were determined. The L-shell satellites of the diagram and of the hypersatellite lines were resolved. The data are interpreted in terms of the properties of He-like hole states in mid- Z atoms. The Breit interaction correction is determined. The corrections due to the unresolved M-shell satellites and to the QED are found to be much smaller than the Breit terms and comparable to the experimental accuracy.

Average energy shifts of K and K x-ray satellite lines and K/K intensity ratios have been experimentally evaluated for a 80Se target bombarded by various projectiles with atomic numbers in the region 3 Zp16 at a given projectile energy of 3.3 MeV/u. The data have been analysed using an approach, based on the results of extensive single-configuration Dirac-Fock (DF) calculations, performed within the multiconfiguration DF method for various distributions of holes in subshells of a 80Se ion. This provides information about the average number of holes in various subshells of 80Se ions at the time of emission of the K x-ray lines. The primary average number of L- and M-shell holes in a 80Se target produced at the moment of collisions with projectiles and the average ionization probabilities per electron for L and M shells have been deduced by means of a simple statistical scaling procedure which accounts for all processes that modify the number of L- and M-shell holes prior to the K x-ray emission. It has been found that the average ionization probabilities per electron for L and M shells increase considerably with Zp2. For larger Zp the average ionization probability per electron is significantly higher for M shells than for L shells. On the other hand, for small Zp the ionization probability per electron seems to be slightly higher for L shells than for M shells. Moreover, the dominant role of the simultaneous multiple ionization of L and M shells accompanying the ionization of a K shell has been observed for projectiles with Zp>3.

Kβ/Kα X-ray intensity ratios of V and Ni in V x Ni 1− x alloys for different compositions x ( x = 0.00, 0.10, 0.20, 0.35, 0.50, 0.75, 1.00) have been measured following excitation by 59.54 keV γ-rays from a 200 mCi 241 Am point-source. The experimental data indicate deviations of Kβ/Kα intensity ratios for V and Ni in certain alloy compositions from the corresponding ratios for pure metals. These deviations of Kβ/Kα intensity ratios have been interpreted using the results of multiconfiguration Dirac–Fock (MCDF) calculations for various valence electronic configurations. Our analysis indicates that the relative changes of the number of 3d electrons (i.e. the changes divided by the number of 3d electrons for pure metals) for V and Ni seem to be very similar if considered as functions of their own concentrations. Comparison (for different x ) of the change of the number of 3d electrons of V with appropriately rescaled change of the number of 3d electrons of Ni indicates that the transfer of 3d electrons between V and Ni seems to explain the observed change of the valence electronic configurations of V and Ni in V x Ni 1− x alloys, although other processes, like the rearrangement of electrons between 3d and (4s, 4p) states, cannot be excluded as being responsible for this change. It is very interesting that the presumed transfer of 3d electrons is from atoms of an element (V or Ni) of a higher concentration to atoms of an element of a lower concentration.