Search

{ital M}-shell x-ray production cross sections for selected heavy elements, namely, {sub 72}Hf, {sub 73}Ta, {sub 74}W, {sub 75}Re, {sub 76}Os, {sub 77}Ir, {sub 78}Pt, {sub 79}Au, {sub 83}Bi, and {sub 90}Th, were measured for protons of energy 0.6--4.0 MeV. The experimental results are compared with the predictions of the first Born and semiclassical approximations for {ital M}-shell ionization; these data are also compared with the theory that accounts for the projectile's energy loss and Coulomb deflection as well as for the target's {ital M}-shell electron perturbed stationary state and relativistic nature (ECPSSR). Generally, fair agreement between the data and the ECPSSR theory is found. Some systematical discrepancies observed for the lightest elements (Hf, Ta, and W) are explained as possible ambiguities in the {ital M}-shell Coster-Kronig factors and fluorescence yields, which were used to convert theoretical {ital M}-subshell ionization cross sections to the total {ital M}-x-ray production cross sections. The experimental total {ital M}-shell ionization cross sections were obtained from measured {ital M}-x-ray cross sections using the proposed approximate average fluorescence yield {bar {omega}}{sub {ital M}} that relies on two fluorescence yields and the Coster-Kronig factor for {ital only} {ital M}{sub 4} and {ital M}{sub 5} subshells.

Measurements of M-shell X-ray production cross sections in selected heavy elements (73 ≤ Z2 ≤ 90) have been performed for proton impact of energy 0.1–0.6 MeV. X-rays were collected by a Si(Li) detector, carefully calibrated for low-energy efficiency, and they were normalized to the projectiles that were elastically scattered into the surface barrier detector. The measured M-X-ray production cross sections are compared with the predictions of the first Born approximation, the semiclassical approximation, and the ECPSSR theory which corrects for energy loss, Coulomb deflection, binding-polarization and relativistic effects. The comparison of the present data with our earlier measurements and the data reported by other authors is discussed in detail. Strong underestimation (up to a factor of about 5) of experimental data by the ECPSSR theory is observed for the lowest energies.

M-shell X-ray production cross sections for Au targets have been measured by 1 H, 3 He and 4 He ions in the energy range 0.6–4.0 MeV. The Si(Li) detector efficiency in the low-energy X-ray region (1.5–4 keV) was carefully determined using the PIXE method. The elastically scattered projectiles were detected by a surface-barrier detector to normalize X-ray yields. The measured X-ray yields were converted to M-shell X-ray production cross sections and then, using average M-shell fluorescence yields evaluated according to relativistic calculations of Chen et al., the total M-shell ionization cross sections were derived. The experimental M-shell ionization cross sections are compared with results reported by other authors and with the predictions of the first-order theories, namely, the PWBA and SCA approximations and also the ECPSSR theory, which accounts for energy-loss, Coulomb deflection, binding-polarization, and relativistic effects.

We demonstrate that in order to interpret the x-ray satellite structure of Pd Lα1,2(L₃M4,5) transitions excited by fast O ions, which was measured using a high-resolution von Hamos crystal spectrometer, the vacancy rearrangement processes, taking place prior to the x-ray emission, have to be taken into account. The measured spectra were compared with the predictions of the multi- con.guration Dirac-Fock (MCDF) calculations using the fluorescence and Coster- Kronig yields which were modiffed due to a reduced number of electrons available for relaxation processes and the effect of closing the Coster-Kronig transitions. We demonstrate that the vacancy rearrangement processes can be described in terms of the rearrangement factor, which can be calculated by solving the system of rate equations modelling the flow of vacancies in the multiply ionized atom. By using this factor, the ionization probability at the moment of collision can be extracted from the measured intensity distribution of x-ray satellites. The present results support the independent electron picture of multiple ionization and indicate the importance of use of Dirac-Hartree-Fock wave functions to calculate the ionization probabilities.

X-ray resonant Raman scattering (RRS) spectra of Al, Al{sub 2}O{sub 3}, Si, and SiO{sub 2} were measured at the European Synchrotron Radiation Facility, using a high-resolution Bragg-type curved crystal spectrometer. The x-ray RRS spectra were collected at several beam energies tuned below the 1s absorption thresholds of Al and Si. Differences in the spectral features between the elemental samples and the oxide ones were clearly observed. The data were interpreted using the second-order perturbation theory within the Kramers-Heisenberg (KH) approach. It is shown that, using the KH formalism, oscillator strengths that are similar to the ones deduced from x-ray absorption measurements can be extracted from emission x-ray RRS spectra. The total cross sections for the x-ray RRS process were derived for the different photon beam energies and compared with theoretical predictions. For elemental silicon, the weak 1s-3p excitation was observed and found to be consistent with results of density of states calculations.

The x-ray satellite structure of Pd Lalpha1,2(L3M4,5) transition excited by an impact of O7+ and Ne6+ ions with energies 279 and 178 MeV, respectively, which were measured using a high-resolution von Hamos crystal spectrometer, is discussed in terms of the multi-configuration Dirac-Fock (MCDF) calculations. We demonstrate, by using the arguments of the general central limit theorem (GCLT), that a structure of complex M-shell satellites of Pd Lalpha1,2(M-m) transitions for a higher number of spectator vacancies (m > 4), which consists of hundreds of thousands of individual x-ray transitions as obtained from the MCDF calculations, can be well described by a single Voigtian profile. The Lorentzian width of such Voigtian line can be well modeled by using the results of the MCDF calculations for simpler configurations with a number of vacancies m < 4 . This method allows one to describe realistically a complex structure of M-shell satellites, thus extending the applicability of the MCDF calculations, which are limited by an increasing complexity of numerical calculations.

X-ray spectra of multicharged xenon ions created in an electron-beam ion trap (EBIT) were measured both with a low-resolution silicon drift detector (SDD) and a high-resolution Johann/Johannson type crystal diffraction spectrometer. The measurement were performed in the electron-beam ion source (EBIS) using the transmission, leaky and pulsed modes of the ion source operation with trapped xenon ions excited by an electron beams of energies 9-15 keV. Moreover, the dynamics and equilibration of the EBIT plasma was studied by measuring the X-ray spectra for different electron energies and trapping times. The results will be discussed using available theoretical models describing the atomic processes in the EBIT plasma.

High energy resolution off-resonant X-ray emission spectroscopy (HEROS) was applied to study one-photon (OPA) and two-photon absorption (TPA) processes in metallic copper generated by ultra-short hard X- ray FEL pulses from the Linac Coherent Light Source (LCLS). The OPA and TPA signals were measured using a multiple-crystal von Hamos diffraction spectrometer allowing observation of both the intermediate and final states in the TPA process. The universal scaling of TPA/OPA cross sections is discussed.

We report on nonlinear interaction of solid Fe with intense femtosecond hard x-ray free-electron laser (XFEL) pulses. The experiment was performed at the CXI end-station of the Linac Coherent Light Source (LCLS) by means of high- resolution x-ray emission spectroscopy. The focused x-ray beam provided extreme fluence of ~105 photons/A2. Two-photon absorption leading to K-shell hollow atom formation and to single K-shell ionization of solid Fe was investigated.

We report on the first high-resolution measurements of the K x-ray resonant Raman scattering (RRS) in Si. The measured x-ray RRS spectra, interpreted using the Kramers-Heisenberg approach, revealed spectral features corresponding to electronic excitations to the conduction and valence bands in silicon. The total cross sections for the x-ray RRS at the 1s absorption edge and the 1s-3p excitation were derived. The Kramers-Heisenberg formalism was found to reproduce quite well the x-ray RRS spectra, which is of prime importance for applications of the total-reflection x-ray fluorescence technique.

High-resolution measurements of the resonant X-ray Raman scattering (RRS) of Al and Si and their oxides were performed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, using a von Hamos Bragg-type curved crystal spectrometer. To probe the influence of chemical effects on the RRS X-ray spectra, Al 2 O 3 and SiO 2 samples were also investigated. The X-ray RRS spectra were measured at different photon beam energies tuned below the K-absorption edge. The measured spectra are compared to results of RRS calculations based on the second-order perturbation theory within the Kramers–Heisenberg approach.

The $M$-shell ionization in high-$Z$ atoms by low-energy light $_{1}^{1}\mathrm{H}$, $_{1}^{2}\mathrm{H}$, $_{2}^{3}\mathrm{He}$, and $_{2}^{4}\mathrm{He}$ ions have been studied systematically in the energy range $0.1--1.0\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}∕\mathrm{amu}$ in order to verify the available theoretical approaches describing the $M$-shell ionization by charged particles in asymmetric collisions. The present low-energy data, combined with our earlier results reported for $M$-shell ionization by hydrogen and helium ions for higher energies, form a systematic experimental basis to test the theoretical predictions of $M$-shell ionization based on the plane-wave Born approximation (PWBA), the semiclassical approximation (SCA), and the binary-encounter approximation (BEA). In the PWBA based approaches the energy loss (E), Coulomb deflection (C), perturbed stationary state (PSS), and relativistic (R) effects were considered within the ECPSSR theory and its recent modification, called the ECUSAR theory, in which a description of the PSS effect was corrected to account for the united- and separated-atom (USA) electron binding energy limits. In the SCA calculations with relativistic wave functions the binding effect was included only in the limiting cases of separated-atom and united-atom limits. Possible contribution of the electron capture, multiple ionization, and recoil ionization to the $M$-shell vacancy production, which is dominated for light ions impact by direct single ionization process, are also discussed. The universal scaling of measured $M$-shell x-ray production and ionization cross sections was investigated in detail. Using the present data the isotopic effect has been studied by comparing the measured $M$-shell ionization cross-section ratios for equal-velocity hydrogen $_{1}^{1}\mathrm{H}$ and $_{1}^{2}\mathrm{H}$ as well as helium $_{2}^{3}\mathrm{He}$ and $_{2}^{4}\mathrm{He}$ isotopes. In addition, the ratios of measured ionization cross sections for $_{1}^{2}\mathrm{H}$ and $_{2}^{4}\mathrm{He}$ were used to investigate the role of the binding effect. The present results are of practical importance for the application of particle-induced x-ray emission technique in trace element studies.

K-X-ray spectra of Zr, Nb, Mo and Pd targets bombarded with 250 MeV carbon and 360 MeV oxygen ions are studied with high resolution diffraction spectrometry. Relative yields and natural widths of the Khα1,2 hypersatellite lines are determined and compared with those of the diagram lines. The widths of Khα1,2 lines are compared with the new phenomenological formula which takes into account the retardation of the Khα₁ transition in the LS coupling scheme. The data significantly exceed the expected values. Deduced lifetimes of the double K-hole states are shorter than expected.

The K{beta}{sub 2} x-ray spectra of zirconium, niobium, molybdenum, and palladium targets bombarded with 20.8-MeV/amu {sup 12}C ions were measured with a high-resolution transmission-type bent crystal spectrometer. Well resolved M{sup 1} and M{sup 2} satellite lines were observed. Average M-shell and 3s,p- and 3d-subshell ionization probabilities for nearly central collisions were deduced. These values are compared with theoretical predictions from the semiclassical approximation using hydrogenlike and Dirac-Hartree-Fock wave functions. The experimental energy shifts of the K{beta}{sub 2} M{sup m=1,2} satellite lines are compared with values obtained from extensive multiconfiguration Dirac-Fock calculations.

The multiple-ionization and coupling effects in L-shell ionization of atoms by heavy-ion impact have been studied by measuring the L x-ray production cross sections in solid targets of Au, Bi, Th, and U bombarded by oxygen ions in the energy range 6.4--70 MeV. The measured L x-ray spectra were analyzed using the recently proposed method accounting for the multiple-ionization effects, such as x-ray line shifting and broadening, which enables one to obtain the ionization probabilities for outer shells. The L-subshell ionization cross sections have been obtained from measured x-ray production cross sections for resolved $L{\ensuremath{\alpha}}_{1,2},$ $L{\ensuremath{\gamma}}_{1},$ and $L{\ensuremath{\gamma}}_{2,3}$ transitions using the L-shell fluorescence and Coster-Kronig yields being substantially modified by the multiple ionization in the M and N shells. In particular, the effect of closing of strong ${L}_{1}\ensuremath{-}{L}_{3}{M}_{4,5}$ Coster-Kronig transitions in multiple-ionized atoms was evidenced and discussed. The experimental ionization cross sections for the ${L}_{1},$ ${L}_{2},$ and ${L}_{3}$ subshells have been compared with the predictions of the semiclassical approximation (SCA) and the ECPSSR theory that includes the corrections for the binding-polarization effect within the perturbed stationary states approximation, the projecticle energy loss, and Coulomb deflection effects as well as the relativistic description of inner-shell electrons. These approaches were further modified to include the L-subshell couplings within the ``coupled-subshell model'' (CSM). Both approaches, when modified for the coupling effects, are in better agreement with the data. Particularly, the predictions of the SCA-CSM calculations reproduce the experimental L-subshell ionization cross section reasonably well. Remaining discrepancies are discussed qualitatively, in terms of further modifications of the L-shell decay rates caused by a change of electronic wave functions in multiple-ionized atoms.

We report here on the results of Monte-Carlo simulations of the radiative recombination of highly charged ions with low-energy electrons in the presence of a guiding magnetic field. The simulations are based on a semi-classical geometrical model, recently proposed by our group, which has been developed in order to explain systematic discrepancies, the so-called 'enhancement effect', of the radiative recombination rates measured in the guiding magnetic field of electron coolers with respect to theoretical calculations. With the simulations, we demonstrate that the enhancement of radiative recombination rates in the magnetic field could be caused by 'transverse' collisions with the impact parameter in the μm range and the impact parameter cut-off value depending on the strength of the guiding B-field in magnetized plasma. In this paper, the methodology of the simulations, the obtained B-field dependence of the radiative recombination enhancement and the observed impact parameter cut-off will be discussed.

We give analytical formulas for the cross section and rate coefficient for radiative recombination between bare ions and free electrons into a fixed n state. Those were derived in the low-energy regime within the nonrelativistic dipole approximation by using the sum rule given by Burgess. An analytical expression for the low-energy Gaunt factor is also derived. The results are briefly discussed in the context of current atomic physics experiments using the electron cooler in heavy ion storage rings.

Multiple ionization in M-, N- and O-shells in solid Au, Bi, Th and U targets was studied for Oq+, Siq+ and Sq+ ions of energies 0.4–2 MeV/amu under charge equilibration condition. From L-x-rays, detected by Si(Li) detector, the ionization probabilities for M- and N-shells were derived. This was done by fitting the measured spectra using a developed model, which describes x-ray energy shifts and line broadening in terms of the ionization probabilities. Derived ionization probabilities are compared with the predictions of the geometrical model (GM). For M- and N-shell the data agree quite well with calculations. The ionization probabilities for O-shell, estimated from line intensity ratios, are in strong disagreement with theoretical predictions, indicating an influence of solid state effects. An importance of multiple ionization effects on derivation of L-subshell ionization cross sections is evidenced and discussed.

M-shell ionization in selected heavy atoms (Au, Bi, Th and U) by energetic Cq+, Nq+ and Oq+, ions of different charge states (q=1–6) has been studied in the energy range 0.1–2 MeV/amu. The measurements were performed using target thicknesses allowing ion charge equilibration in the target. Derived equilibrium M-shell ionization cross sections are compared with the theoretical predictions based on the semiclassical (SCA) and the PWBA approximations for direct ionization and the OBK approximation for the electron capture, as well as the ECPSSR theory including the corrections for higher-order effects. Substantial contribution of the electron capture caused by the ion charge equilibration is observed for high energies. The influence of the multiple ionization in M-, N- and O-shells on measured cross sections is discussed.

The Kα hypersatellite X-ray spectrum of 42Mo target bombarded with 17 MeV/u 16O ions was measured with a high-resolution transmission bent crystal spectrometer. Well resolved lines of L-satellites and K-hypersatellites of Kα1 and Kα2 transitions were observed. Such data give valuable and rich information for testing the approximation used for the description of the multielectron system. The Khα1 hypersatellite, treated as spin-flip 1S0→3P1 transition, is forbidden in pure L-S coupling. In that case the relative yields of the Kα hypersatellites reflect directly the degree of intermediate coupling in the atom. Moreover, energies of the Khα1.2L0,1 transitions and the I(Khα1L0,1)/I(Khα2L0,1) intensity ratios are much more influenced by the Breit interaction than the diagram lines. The discussion of these problems is illustrated with the measured Kα hypersatellite spectrum of 42Mo.

The ray tracing simulations of x-ray spectra for a compact six-crystal Johann/Johansson diffraction spectrometer covering a wide photon energy range (70 eV–15 keV), i.e. from the extended ultraviolet to the hard x-ray region, are discussed in the context of x-ray experiments at an electron beam ion source facility. In particular, the x-ray line profiles and energy resolution for different diffraction crystals and multilayers were studied, and the effects of extension of x-ray source size and misalignment were investigated. The simulations were also performed for x-ray emission from solid targets bombarded by electrons, which will be used for calibration of the x-ray spectrometer.

We report on the calculations of the K-shell differential radiative recombination (RR) rate coefficients for very low, in the range of meV, relative electron–ion energies. The rate coefficients were derived for bare uranium ions colliding with free electrons both within the nonrelativistic dipole approximation and using fully relativistic calculations. We show that even for such low relative ion–electron energies, the differential rate coefficient reveals strong relativistic effects. We demonstrate that the measurements of the relative electron energy dependence of the RR rates represent a very sensitive tool for precise studies of the RR process and, in particular, for probing the fine details of the relativistic effects in the RR of ions with electrons. The results are discussed in the context of the first x-ray state-selective RR experiment performed for very low relative electron–ion energies.

Observed enhancement of K-shell radiative recombination (RR) of bare uranium ions with cooling electrons is interpreted in terms of of distant transverse collisions in magnetized electron-cooler plasma described within the semiclassical geometrical model (SGM), which was recently proposed. The Monte Carlo simulations based on the proposed approach explains the enhancement measured in RR of U^{92+} ions with cooling electrons for the K-shell.

New interpretation of the enhancement effect in the radiative recombination (RR) of bare ions with with cooling electrons in cooler/storage rings is proposed which explains this effect by the transverse collisions with large impact parameter, in the μm range, in the magnetized anisotropic plasma in the electron cooler. The developed simplified approach, called the semiclassical geometrical model (SGM), predicts for a weak magnetic fields the scaling of RR excess rate which agrees with experimental observations. Detailed Monte Carlo simulations of the RR in the magnetized electron-cooler plasma based on the proposed SGM model explains the enhancement observed in ion storage rings in RR experiments.

L-shell x-ray production and subshell ionization cross sections have been measured for 0.4--1.8-MeV/amu carbon and nitrogen ions for selected heavy elements with 72\ensuremath{\le}${\mathit{Z}}_{2}$\ensuremath{\le}90. The results are compared with the predictions of the ECPSSR theory [perturbed-stationary-state (PSS) theory with energy-loss (E), Coulomb deflection (C), and relativistic (R) corrections] describing both direct ionization and electron-capture processes and the semiclassical approximation (SCA) calculations for direct ionization. For both theories significant deviations are found for ${\mathit{L}}_{2}$-subshell ionization in the low-energy range. The multiple ionization of outer shells was studied by comparing L x-ray intensity ratios measured for heavy ions and protons. The ionization probabilities of the ${\mathit{N}}_{4}$ subshell at zero impact parameter was extracted from these data. Measured ionization probabilities are compared with the predictions of the SCA theory and the ``geometrical model.'' The influence of multiple ionization on the measured L-subshell cross sections is discussed.

We have measured the \ensuremath{\Delta}N=1 dielectronic recombination cross sections of hydrogenlike helium. Recombination rates were investigated as ${\mathrm{He}}^{+}$ ions interacted with free electrons in the electron-cooler section of an ion storage ring. The ion beam was cooled prior to recombination, resulting in enhanced energy resolution. Fits to the 2l2l' resonances yielded transverse and longitudinal temperatures of ${\mathit{kT}}_{\mathrm{\ensuremath{\perp}}}$=0.15 eV and ${\mathit{kT}}_{\mathrm{\ensuremath{\parallel}}}$=0.8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ eV, respectively. The resulting peak widths are approximately 0.3-eV full width at half maximum. The measured integrated cross sections are in qualitative agreement with calculated resonance strengths.

The status of the new EBIS-A irradiation facility constructed by the Dreebit GmbH company, Dresden, for the new laboratory at the Jan Kochanowski University (JKU) in Kielce designed for the studies of ion-matter interactions is presented. The facility will be used for the interdisciplinary studies involving atoms, molecules, plasmas, surfaces and cells by taking an advantage of low-energy highly charged ions (HCI) and x-ray spectroscopy techniques. The EBIS-A facility, consisting of an EBIT-type ion source, beam guiding and diagnostic system, double focusing analyzing magnet and multipurpose target chamber, offers new opportunities for performing the experiments on slow, highly charged ions colliding with matter, including such different phenomena as formation of nanostructures in ion-surface interactions, recombination processes in plasma, fragmentation of biomolecules by ion and electron impact and the radiobiological effects in living cells. In this paper a concept of the EBIT/X-ray laboratory, construction details of the EBIS-A facility, the physics program, based on our former experimental activities in the atomic and molecular collisions, and application of x-ray spectroscopy in materials science are discussed.

Radiative recombination of bare ions with electrons is discussed as a time-reversed photoionization process in the nonrelativistic dipole approximation. Analytical expressions for the radiative-recombination cross section and the angular distribution of the emitted photons are derived for an arbitrary (n,l) state in the low-energy limit. In this approximation, the anisotropy of the emitted photons is described by an energy-independent parameter ${\mathrm{\ensuremath{\beta}}}_{\mathit{n}\mathit{l}}$. The radiative-recombination rate coefficients, both differential and angle integrated, for any (n,l) state can, in this limit, be expressed in analytical form. This result holds also for an anisotropic electron-velocity distribution characterized by a longitudinal ${\mathit{kT}}_{\mathrm{\ensuremath{\parallel}}}$ and transverse ${\mathit{kT}}_{\mathrm{\ensuremath{\perp}}}$ electron-beam temperatures. The results are discussed in context of the state-selective radiative-recombination experiments planned to be studied in electron coolers of heavy-ion storage rings.

The observation of the enhancement of radiative recombination (RR) into the K-shell for U92+ ions interacting with cooling electrons in x-ray RR experiment performed at the ESR storage ring is reported. From the measured intensities of K-RR x-rays for the electron relative energies in the range 0-1000 meV a clear indication of the recombination enhancement, with respect of the fully relativistic RR calculations, was found for the K-shell for the zero relative electron energy. This results add new aspects to existing interpretations of the enhancement effect emphasizing a role of recombination into high Rydberg states.

The interpretation of L-shell satellites and hypersatellites for Lα1,2 (L3→M4,5) and Lβ1 (L2→M4) x-ray transitions in zirconium multiply ionized by oxygen and neon ions is reported. The x-ray spectra were measured with a high-resolution von Hamos spectrometer and interpreted in terms the relativistic multi-configuration Dirac-Fock (MCDF) calculations. The ionization probabilities of L- and M-shell derived from the data are compared with the predictions of the semiclassical approximation (SCA) calculations.

We report on the application of synchrotron radiation based high-resolution grazing-emission x-ray fluorescence (GEXRF) method to measure low-level impurities on silicon wafers. The presented high-resolution GEXRF technique leads to direct detection limits of about 10¹² atoms/cm². The latter can be presumably further improved down to 10⁷ atoms/cm² by combining the synchrotron radiation-based GEXRF method with the vapor phase decomposition preconcentration technique. The capability of the high-resolution GEXRF method to perform surface-sensitive elemental mappings with a lateral resolution of several tens of micrometers was probed.

Extensive multiconfiguration Dirac-Fock (MCDF) calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on molybdenum to explain the dependence of the structure of L? 1,2 and L? 1 lines on the changes in configurations of the valence electrons belonging to two different configuration types: three open-shell 4d6-r5sr (r = 2,1,0) configurations and one closed-shell 4d43/2 5s2 configuration. It has been found that the MCDF predictions for open-shell valence configurations (4d4 5s2, 4d5 5s1, 4d6 5s0) much better reproduce observed structure of L? 1,2 lines in X-ray spectra of molybdenum than closed-shell 4d43/2 5s2 valence configuration. The influence of changes in the valence electronic configuration on the structure of L-X-ray spectra of molybdenum is noticeable. Moreover, the observation of the shapes of L-X-ray spectra seems to be very good method to investigate the changes of the valence electronic configuration caused by the chemical environment.

Individual X-ray lines and total L-shell X-ray production cross sections for Ag, Sn, Sb, Te, Ho, Ta, W, Pt and Bi thin targets have been measured as a function of 4He-ion energy from 1.5 to 3.8 MeV. Comparison between theoretical and experimental values of individual and total L-shell cross sections and their ratios has been made and discussed. The theoretical values have been calculated in the plane-wave Born approximation including corrections for the binding energy, polarisation, Coulomb deflection, energy loss and relativistic effects (ECPSSR theory). The influence of collisionally-induced alignment on measured cross sections is discussed.

The 12C(12C, α)20Ne reaction is studied near Ec.m. = 15 MeV. Angular distributions for three energies and excitation functions at θlab = 30° over an energy range Ec.m. = 14.5−15.4 MeV for about 20 levels in 20Ne (Eex = 0–13 MeV) are examined. The statistical analysis yields the results that a correlated resonance is present at Ec.m. = 14.75 MeV. A nonstatistical contribution to the reaction is also apparent when energy-averaged cross sections are compared with the Hauser-Feshbach model predictions. Strong population of the 0+3 band in 20Ne is observed.

The K-shell X-ray production cross sections and Kbeta /Kalpha ratios have been measured for thin targets of Ti, Rb, Zr, Nb, Mo, Pd, Ag and Sb by protons and for thin targets of Ti, Cr, Co, Cu, Se, Rb, Zr, Nb, Mo, Pd, Ag and Sn by 4He ions over the energy range of 1.5-3.8 MeV. The ionisation cross sections were calculated using atomic K-shell fluorescence yields and compared with the plane-wave Born approximation (PWBA) modified to included the effects of relativity, increasing target electron binding energy, target electron polarisation, Coulomb deflection of the incident particle and energy-loss effects in the ionisation process, resulting in the ECPSSR theory. The universal character of K-shell ionisation cross sections is discussed. The Kbeta /Kalpha ratios are compared with theoretical predictions and with results reported by other authors.

The technique of the hydrogen depth profile determination by proton elastic recoil detection using 4He ion beams with energy 2.0 to 2.5 MeV from the Van de Graaff accelerator is described. The hydrogen concentration profiles are obtained by simulating the experimental proton recoil spectra taking into account the effects of energy straggling and multiple scattering in the target and Al stopper foil and the detector energy resolution. The method is tested using multilayer hydrogen target and Mylar foil and is applied to hydrogen profile determination in H implanted Si crystals. [Russian Text Ignored].

Thin targets of Sb, Te, Ho, Ta, W, Pt and Bi have been employed and L X-ray yields have been measured as a function of proton energy from 1.5 to 3.8 MeV. From these measurements the individual and total X-ray production cross sections and their ratios have been calculated and compared with the experimental results reported by other authors and with the perturbed stationary-state plane-wave Born approximation with correction for Coulomb deflection, relativistic and energy-loss effects resulting in the ECPSSR theory of Brandt and Lapicki (1979, 1981).

The chemotherapy and photon radiotherapy are the most often applied methods in treatment of the cancer diseases because of their effectiveness and high cure rates. Apart from eligible destruction of the tumour, one of the side effects of these treatment methods is possible modification of main and trace element concentration in different human tissues and fluids. In this paper, the copper (Cu) level in human serum was determined by total reflection X-ray fluorescence method in 142 chemotherapy patients and in 44 healthy persons being a control group. The Cu concentration in the chemotherapy group was found to be on the level 1.78 ± 0.909 mg/L, while in the control group, it was 1.08 ± 0.551 mg/L. Performed measurements allowed for calculation of the parameters of copper concentration distribution (mean value, standard deviation, median) for both analysed groups. The theoretical nature of the concentration distribution was tested and found as a log-normal distribution (control group) and a log-stable distribution (chemotherapy group). The copper concentration distributions for both studied group were statistically compared using Kolmogorov-Smirnov test, and the conclusion was that the distributions are statistically different. Serum Cu levels were significantly higher in the chemotherapy group than in the control group. Taking into account the results for the control group, the copper concentration reference quantile ranges in human serum were obtained. The values of the mean, median and other quantiles determined in this case can be applied in two-group comparison studies. The obtained results can be used as a diagnostic tool for chemotherapy patients.

The L-X-ray production cross sections for L α1, 2 , L γ 1, 5 and L γ2, 3, 6 transitions have been measured for thin targets of nine heavy elements (Ag, Sn, Sb, Te, Ho, Ta, W, Pt and Bi) by proton and helium ion impact in the energy range 1.5 to 3.8 MeV. The ionisation cross sections for the L 1 , L 2 and L 3 subshells were extracted using fluorescence and Coster- Kronig yields of Krause and emission rates of Scofield. The influence of the uncertainties of these atomic parameters on the resulting cross sections was taken into account and discussed. The measured L-subshell ionisation cross sections were compared with results reported by other authors and with predictions of the ECPSSR theory of Brandt and Lapicki. Possible explanations for the observed discrepancies for the L 1 −, L 2 − and L-subshells are discussed.

The influence of plasma effects on three-body recombination of bare ions with electrons in cold plasma in the electron cooler is discussed in context of recombination "enhancement" observed in storage ring experiments. We show that for high-Z bare ions and low electron temperatures and densities the cooler plasma becomes "nonideal", leading to the enhancement of the three-body recombination rates. This effect is described in terms of the Debye screening length within the "rigid shift" approximation. We demonstrate, that in cold (T ≈ 1–10 K) anisotropic plasma the screening effect substantially enhances the three-body recombination rates for very high n-states. The relaxation of high Rydberg states below the field ionization cut-off, set in storage ring experiments, is discussed. The calculations are confronted with the experimental results obtained in storage ring experiments.

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.