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The measurements of the M- and N-shell ionization probabilities in gold bombarded by highly charged S q+ (q = 4–14) ions of energy 0.4–3.8 MeV/amu are reported. The ionization probabilities were extracted from the measured L-X-ray spectra which were substantially modified by the multiple ionization effects. The observed L-X-ray line shifts and broadening allowed us (Banaś et al., 2002) to extract both the M- and N-shell ionization probabilities for the zero impact parameter. These ionization probabilities, which correspond to the moment of X-ray emission , were correlated with the ionization probabilities for the moment of ion impact ionization by using the vacancy rearrangement procedure developed here. In this way the ionization probabilities for the moment of ion impact multiple ionization were obtained. By comparing to the theoretical predictions of the semiclassical approximation (SCA) (Trautmann and Kauer, 1989) and the “geometrical model” (GM) (Sulik et al., 1987) based on the binary encounter approximation (BEA), the role of the electronic wave functions and the binding effect is discussed. Generally, the calculations using the hydrogenic wave functions reproduce the measured ionization probabilities.

Particle-induced X-ray emission (PIXE) technique is usually applied using typically 1 MeV to 3 MeV protons or helium ions, for which the ion-atom interaction is dominated by the single ionization process. For heavier ions the multiple ionization plays an increasingly important role and this process can influence substantially both the X-ray spectra and atomic decay rates. Additionally, the subshell coupling effects are important for the L- and M-shells ionized by heavy ions. Here we discuss the main features of the X-ray emission induced by heavy ions which are important for PIXE applications, namely, the effects of X-ray line shifts and broadening, vacancy rearrangement and change of the fluorescence and Coster–Kronig yields in multiple ionized atoms. These effects are illustrated here by the results of the measurements of L X-ray emission from heavy atoms bombarded by 6 MeV to 36 MeV Si ions, which were reported earlier. The strong L-subshell coupling effects are observed, in particular L 2 -subshell, which can be accounted for within the coupling subshell model (CSM) developed within the semiclassical approximation. Finally, the prospects to use heavy ions in PIXE analysis are discussed.

The L-shell X-ray production cross sections have been measured for sulphur ions in the energy range of 12.8–120 MeV for Au and Bi elements. The experimental L X-ray spectra were analyzed using the method that takes into account the multiple ionization in outer shells. The L-subshell ionization cross sections have been obtained from measured X-ray production cross sections for resolved Lα 1,2 Lγ 1 and Lγ 2,3 transitions using the L-shell fluorescence and Coster–Kronig yields modified by the multiple ionization effects in the M and N shells. The results are compared with the predictions of ECUSAR theory, which is the modified ECPSSR approach describing both direct ionization and electron-capture processes and the semiclassical approximation (SCA) calculations for direct ionization. These approaches were modified by the L-subshell coupling effects within the “coupled-subshell model” (CSM). Both modified approaches are in good agreement with the data. Remaining discrepancies are discussed in terms of the L-shell decay rates modified for the multiple ionization effects.

The coupling and binding effects in ionization of L-shell electrons by heavy ions have been studied by measuring the L γ (L–N,O) X-ray transitions in gold excited by an impact of O, Si and S ions in the energy range 0.3–5 MeV/amu. The L-subshell ionization cross sections were extracted from measured X-ray spectra taking into account their substantial modifications due to the multiple ionization effects, which also change the fluorescence and Coster–Kronig yields. In order to interpret the data the L-subshell couplings were incorporated in the theoretical calculations based on the semiclassical approximation (SCA) within the “coupled subshell model” (CSM). Resulting SCA–CSM calculations, which describe the data for oxygen ions quite satisfactory, are further modified to include the saturation of the binding effect in order to describe the data for heavier Si and S ions. We find that the semiclassical SCA–CSM calculations of L-shell ionization by heavy ions ( Z 1 ≫ 1), which include corrections both for coupling and binding saturation effects, agree reasonably well with the measured data.

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.

The evolutions of the track diameters in the PM-355 Solid Stated Nuclear Track Detector irradiated with normal incident of S and Ar ions of energy within a few MeV/amu range are reported. Also a comparison of the calibration diagrams as obtained for4He projectiles and and different etching times of PM-355 detectors etched a few days and ten years after their the irradiations, is presented too.

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 paper discusses the effect of closing of L- and M-shell Coster–Kronig (CK) transitions in multiply ionised Au atoms, for which the selected CK transitions become energetically forbidden. This effect plays an important role when the Coster–Kronig energy for single-hole configuration is relatively low, being comparable with a change of the electronic binding energies in multiply ionised atom. We show, by using a simplified model, that for gold the effect of closing of CK transitions occurs for strong L1–L3M4,5 transition for the L1-subshell as well as the M3–M5N6,7 and M4–M5O3,4 CK transitions for the M3- and M4-subshell, respectively. We demonstrate that the discussed effect of closing CK transitions substantially changes the X-ray fluorescence and Coster–Kronig yields and thus has to be considered in interpretation of X-rays excited by heavy ion impact.

The ionization of L-subshell electrons in gold by the impact of 0.4-2.2 MeV amu-1 O ions was studied by observing excited Lγ(L-N, O) x-rays. We demonstrate that both the multiple ionization in outer M- and N-shells as well as the coupling effects in the L-shell play an important role in understanding the measured L-subshell ionization cross sections. The multiple ionization was found to be important in two aspects: first, the analysis of x-ray energy shifts and line broadening was crucial for proper interpretation of measured x-ray spectra; second, the additional vacancies in the M- and N-shells substantially influenced the L1-subshell fluorescence and Coster-Kronig (CK) yields, mainly by closing strong L1-L3M4,5 CK transitions. The data are compared with the simplified coupled-channels calculations using the `coupled-subshell model' (CSM) based on the semiclassical approximation (SCA), which describes both direct Coulomb ionization as well as the L-subshell couplings within the same theoretical approach. A good agreement of the present data with the theoretical predictions based on the discussed SCA-CSM approach is observed. Present findings partly explain the long-standing problem of inadequate theoretical description of L-shell ionization by heavy ion impact.

The evolutions of track diameters produced in the PM-355 solid-state track detector irradiated with normal incident protons, deuterons, 4 He- and 12 C-ions of energy within a MeV range are reported. Some correlation between observed track diameters, energy of detected particles, their atomic number, and detector material characteristics ( V B , d E /d x , particle range) are presented. It was found that the PM-355 detector is the best one for the detection of light ions, and thereby for corpuscular diagnostics of high-temperature plasma.

Solid-state nuclear track detectors have found wide use in various domains of science and technology, e.g. in plasma experiments. The track detectors used in the fusion-oriented experiments encounter “harsh” conditions (intense X-ray and neutron radiation, heat impact, shock waves and plasma fluxes). Therefore, such detectors should be tested under similar conditions. This paper concerns influence of electron and γ radiation on the track formation in PM-355 detectors. Samples were irradiated with 1.5-MeV protons and 4 He -ions, and with 5.5 MeV α particles. After that they were exposed to γ and electron radiation. Irradiation doses were varied from 100 kGy up to 2000 kGy . The etching was performed in steps, and a bulk etching rate ( V B ) was determined versus an absorbed dose of electron and gamma radiation.

The coupling and binding effects have been studied in $L$-subshell ionization of heavy Au, Bi, Th, and U atoms by an impact of ${^{28}\text{S}\text{i}}^{q+}$ ions in the energy range of 8.5--36.0 MeV. The measured $\mathit{L}$ x-ray spectra were analyzed taking into account the multiple ionization effects in outer $M$ and $N$ shells. The $L$-subshell ionization cross sections have been obtained from measured x-ray production cross sections using the $L$-shell fluorescence and Coster-Kronig yields which were modified for a reduced number of electrons and closed Coster-Kronig transitions in the multiply ionized atoms. The results are compared with the available calculations, which are based on the semiclassical approximation (SCA) as well as the plane-wave Born approximation (PWBA). We demonstrate that for silicon ion impact these theoretical approaches have to be modified to include the $L$-subshell coupling effect using the ``coupled subshell model'' (CSM) as well as the saturation of the binding effect at the united atom limit. The calculations modified for both effects are in much better agreement with the data. In particular, an order-of-magnitude improvement of agreement between the data and the SCA-CSM calculations including the binding-saturation effect is reported for low-energy Si ions for the ${L}_{2}$-subshell. The results are also compared with the predictions of the PWBA based ECPSSR and ECUSAR theories accounting for the energy-loss (E), Coulomb-deflection (C), and relativistic (R) effects treating the binding effect within the perturbed stationary state (PSS) approximation with correction for the binding-saturation effect introduced to describe the united-atom and separated-atom (USA) limits.

The K{alpha} and K{beta} satellite and hypersatellite x-ray lines emitted by highly ionized sulfur projectiles passing with energies from 65 MeV up to 122 MeV through carbon foils of thickness of 15-210 {mu}g cm{sup -2} have been recorded using a Si(Li) detector. The additional hypersatellite Ky{sup h} peak proves that for such high energies of the sulfur ions very high subshells (4p and 5p) could be occupied. In order to study the dynamics of formation of K-shell vacancy fractions of sulfur projectiles passing through a carbon foil the dependence of sulfur K x-ray production cross sections on foil thickness has been examined separately for each recorded line using the three component model. For each projectile energy the values of K-shell hole production cross sections and K-shell electron capture cross sections (both common for all recorded x-ray lines in the case of each projectile energy) have been fitted, as well as the specific values (for each recorded x-ray line) of K-shell hole filling cross sections, which are directly connected with average lifetimes of appropriate states of sulfur ions. The obtained ''experimental'' values of K-shell vacancy production cross sections are much higher than the theoretical predictions. This suggests that apart from themore » ionization process the excitation from K shell into higher shells is responsible for a production of K-shell vacancies, which has been confirmed by recent classical trajectory Monte Carlo calculations.« less

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.