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The Li (i = l, α, β, and γ) production cross-sections, L-shell average fluorescence yields, and Coster-Kronig vacancy transfer factors for L3 subshell X-rays of thallium in some thallium compounds ...

In the modeling approach of Jupiter’s radiation belt, the accurate calculation of magnetic coordinates from geographic coordinates is the basis. In the previous studies, the L-shell parameters are always calculated based on the assumption of a dipole field though the accuracy of this method is low. We present a new L-shell calculation method based on the magnetic field lines tracing method and ANN (Artificial Neural Network). In this method, a compromise between calculation accuracy and speed is achieved. This method consists of a classifier and a predictor. The Classifier is a BP (Back Propagation) ANN based on AdaBoost algorithm and the Predictor is a BP ANN optimized by GA (Genetic Algorithm). The Classifier is used to identify whether the coordinates are within Jupiter’s inner magnetosphere. If so, the Predictor is used to calculate the L-shell parameters. The error rates of the Classifier and the Predictor are 3 and 7%, relatively. In an example of the Juno’s orbit, the calculation speed of this ANN-based method is about 3 orders higher than that based on the magnetic field lines tracing method.

The portability, ease of use, relative lower cost of procurement and simple maintenance of a handheld X-ray fluorescence analyzer makes it a potential alternative for air particulate analysis especially in highly polluted and economically disadvantaged regions of the world. Thus, this study assessed the performance of such analyzer in characterizing aerosol laden filters. Spectra of Certified Reference Materials (NIST 2783 CRM for aerosol filters) measured with a handheld X-ray fluorescence analyzer were calibrated and fitted using iterative nonlinear least-square fitting procedure provided by the International Atomic Energy Agency-Quantitative X-ray Analysis System. Elemental sensitivity calibration curves, method detection limits, uncertainty estimates of K- and L- X-ray lines in the elemental range 18

Funding Information: This research was funded in part by FCT (Portugal) under research center grant UID/FIS/04559/2020 (LIBPhys). This work was also funded through the project PTDC/FIS-AQM/31969/2017, “Ultra-high-accuracy X-ray spectroscopy of transition metal oxides and rare earths”. F.G. acknowledges support from FCT, Portugal through contract UI/BD/151000/2021 . J. M and J.P.S acknowledge the support of EMPIR, Germany , under Contract No. 20FUN04 PrimA-LTD. The EMPIR initiative is co-funded by the European Union’s Horizon 2020 research and innovation programme and the EMPIR, Germany participating States. Part of this work has been carried out under the High Performance Computing Chair - a R&D infrastructure (based at the University of Évora; PI: M. Avillez), endorsed by Hewlett Packard Enterprise (HPE), and involving a consortium of higher education institutions (University of Algarve, University of Évora, NOVA University Lisbon, and University of Porto), research centres (CIAC, CIDEHUS, CHRC), enterprises (HPE, ANIET, ASSIMAGRA, Cluster Portugal Mineral Resources, DECSIS, FastCompChem, GeoSense, GEOtek, Health Tech, Starkdata), and public/private organizations (Alentejo Tourism-ERT, KIPT Colab). Funding Information: This research was funded in part by FCT (Portugal) under research center grant UID/FIS/04559/2020 (LIBPhys). This work was also funded through the project PTDC/FIS-AQM/31969/2017, “Ultra-high-accuracy X-ray spectroscopy of transition metal oxides and rare earths”. F.G. acknowledges support from FCT, Portugal through contract UI/BD/151000/2021. J. M and J.P.S acknowledge the support of EMPIR, Germany, under Contract No. 20FUN04 PrimA-LTD. The EMPIR initiative is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR, Germany participating States. Part of this work has been carried out under the High Performance Computing Chair - a R&D infrastructure (based at the University of Évora; PI: M. Avillez), endorsed by Hewlett Packard Enterprise (HPE), and involving a consortium of higher education institutions (University of Algarve, University of Évora, NOVA University Lisbon, and University of Porto), research centres (CIAC, CIDEHUS, CHRC), enterprises (HPE, ANIET, ASSIMAGRA, Cluster Portugal Mineral Resources, DECSIS, FastCompChem, GeoSense, GEOtek, Health Tech, Starkdata), and public/private organizations (Alentejo Tourism-ERT, KIPT Colab). Publisher Copyright: © 2022 The Author(s) In this work, we present K- and L- shell fluorescence yield values of the full isonuclear sequence of Fe ions, using a state-of-the-art multiconfiguration Dirac–Fock approach. These results may be of importance for spectral fitting and plasma modeling, both in laboratory and astrophysical studies, where Fe is an important benchmark element. The K-shell fluorescence yields were found to be very similar up to the removal of 14 electrons. publishersversion published

Relativistic electron injections are one of the mechanisms of enhancements of relativistic (≥ 0.5 MeV) electrons in the Earth’s outer radiation belt. In this study, we present the statistical observation of 600 keV electron injections in the outer radiation belt using the Van Allen Probes data. Based on the different injection characteristics, 600 keV electron injections in the outer radiation belt are divided into “pulsed electron injections” and “non-pulsed electron injections”. The 600 keV electron injections are observed at over 4.5 < L < 6.4 under the geomagnetic conditions of 450 nT < AE < 1450 nT. L ~ 4.5 is an inward limit for 600 keV electron injections. Before the electron injections, the flux negative L shell gradient for ≤ 0.6 MeV electrons or the low electron fluxes in the injected region are observed. For 600 keV electron injections at different L shells, the source populations from the Earth’s plasma sheet are different. For 600 keV electron injections at higher L shells, the source populations are higher energy electrons (~ 200 keV at X ~ –9 RE), while the source populations for 600 keV electron injections at lower L shells are lower energy electrons (~ 80 keV at X ~ –9 RE). These results are important for our further understanding of electron injections and rapid enhancements of 600 keV electrons in the Earth’s outer radiation belt.

In this work, we experimentally determined Ag and Au L-shell X-ray production and ionization cross sections, induced by 2–5 MeV carbon ions. The experiment was performed using the standard measurement setup already used to measure M-Shell X-ray production cross sections. Ag and Au thin targets, were used to measure L-shell X-ray spectra with Si(Li) and SDD X-ray detectors simultaneously with backscattered carbon ions from the targets by surface barrier detector. Experimental values are compared to the data available in the literature, as well as to the theoretical predictions of PWBA, ECPSSR and ECUSAR models. The analysis of data shows that the ECUSAR predictions are good at low carbon ion energies while the ECPSSR and PWBA predictions agree at the higher incident energies.

The L-shell ionisation and X-ray production cross sections of the elements: Tc, Pm, Os, Po, At, Rn, Ra and Ac, whose experimental cross sections are scanty due to their radioactive, toxic and unstable nature have been calculated. Computer codes were employed in the targets cross sections calculation for incident protons of 1.00–10.00 MeV energy range. The obtained cross sections were validated in a similar procedure for Osmium ( Z 2 = 76 ) induced by protons of energies 0.10–1.00 MeV and were compared with experimental data. The calculated cross sections for the Osmium target were in good agreement with the experimental data. Hence, the calculated cross sections for the considered industrially relevant targets will be a valuable addition to existing database of elements induced by protons.

The L-shell ionisation and X-ray production cross-sections of some post-transition elements: In, Sn and Tl, induced by protons of energies 1 MeV–4 MeV, have been calculated. The targets considered have few experimental cross-sections, for indium and tin, while thallium has no existing cross-section values in the database due to its radioactive and toxic nature. The cross-sections for the targets were obtained using computer codes based on the ECPSSR and SCA theories; and were subsequently validated using lead and bismuth targets whose experimental values are known within this energy range. The comparison of the experimental and calculated cross-sections showed that both models are in good agreement within certain proton energy region. However, above 2 MeV, the ECPSSR models should be employed. For the case where the SCA model is to be employed, the energy loss and Coulomb deflection factors should be taken into account.

L-shell X-ray fluorescence computed tomography based on polychromatic X-rays is a promising imaging technique for early cancer diagnosis. However, the presence of self-absorption and the long scanning time limit its usage in clinic. In this work, a reconstruction method based on split-Bregman algorithm which used sparseview projection data was proposed. Furthermore, the attenuation effect was also considered in the algorithm. In the attenuation correction, factors including the X-ray energy and the platinum concentration were taken into account. Then weighted factors calculated in the procedure of attenuation correction were added into the contribution function of pixels in the split-Bregman based reconstruction method. In the end, the feasibility of this method was tested using a cylindrical phantom with 8 mm in diameter by the Monte Carlo simulation. The phantom contained four inserts, all of which were 1.5 millimeter in diameter and filled with 0.10%, 0.20%, 0.40% and 0.80% platinum solutions, respectively. The results show that both the contrast-to-noise ratios and lowest detectable sensitivities are improved for the proposed method, comparing to the conventional MLEM. The contrast-to-noise ratios of images reconstructed by our method with 45 projections are already better than that reconstructed by MLEM with 60 projections. When using 60 projections in our method and comparing to 60 projections in the MLEM with correction, the contrast-to-noise ratio of the insert filled with 0.10% platinum solutions increased from 6.49 to 36.90, indicating its high efficiency and robustness.

The present status of theoretical L-shell x-ray production cross sections is gauged by an updated and revised fit to 5771 measurements in elements ranging from 24Cr to 95Am in ionization by 0.035 to 1000 MeV protons. Both the theory and the fit are cast with a single scaling variable v1/v2L, which is the ratio of proton velocity to the orbital velocity of the L-shell electron. A review of possible theories shows that the ECUSAR theory extended to relativistic protons provides for the most comprehensive choice for comparison with empirical fit to the compiled data. Both the fit and the theory are in excellent agreement with the compiled data except for cross sections reported at v1/v2L

Polychromatic source X-ray fluorescence computed tomography (XFCT) is a novel imaging method, which is applied for the diagnosis and treatment studies of early stage cancer. In this paper, we propose a fast multi-pinhole L-shell XFCT imaging system to reduce the scan time and radiation dose, which has potential in detecting lower concentration of contrast agents (gold nanoparticles, GNPs). Two kinds of phantoms – the concentration-phantom 1 and the size-phantom 2 are designed to verify imaging performance for low-concentration and small-size ROI. The scanning processes are simulated by Geant4, and images are reconstructed by Optimized EM-TV algorithm. It is concluded that this imaging system is more sensitive in detecting low concentration GNPs than K-shell imaging system. Simulation experiments show the reconstructed images can achieve the highest CNR both for phantom 1 and phantom 2 with iterating 10 times. The detection limit can reach 0.16% when pinhole radius is 0.08mm.

This study explored the influence of foil thickness, laser pulse width, and laser intensity to optimize the multi-keV X-ray conversion efficiency of a sandwiched (CH/Sn/CH) planar target under laser irradiation at the Shenguang II laser facility. The X-ray photon field values were measured using a set of elliptically bent crystal spectrometers and the conversion efficiencies (ξx) of photon energies were in the range of 3.7–4.3 keV. The experimental results indicate that the X-ray yields of 3.7 to 4.3 keV radiation strongly depend on the laser pulse width, target thickness, and laser intensity. The results also demonstrate that three-layer thin foils can provide an efficient multi-keV X-ray source because they can change the distribution of emitted multi-keV X-rays and target dynamics versus nanosecond laser pulses to produce large, hot, and underdense plasma. However, the underdense plasma produced as a rarefaction wave causes the overdense plasma generated by the laser pulse to expand. Therefore, the laser parameters and foil thickness must be carefully optimized to produce an efficient 3.7 to 4.3 keV X-ray source. Otherwise, the rarefaction waves from both sides of the thin foil may suppress multi-keV X-ray emission. This study represents an important advancement in the development of an efficient multi-keV L-shell-band X-ray source.

Multiple ionization of the ${\mathrm{Ar}}^{+}(3{s}^{2}3{p}^{5})$ ion by a single photon has been investigated in the photon-energy range 250--1800 eV employing the photon-ion merged-beams technique. Absolute partial cross sections were measured for all ${\mathrm{Ar}}^{(1+m)+}$ product-ion channels with $1\ensuremath{\le}m\ensuremath{\le}6$ covering a size range from several tens of Mb down to a few b. Narrow $2p$-subshell excitation resonances were observed in all channels up to quadruple ionization at a photon-energy bandwidth of 52 meV. Double excitations involving a $2p$ and a $3s$ or $3p$ electron were also studied at high resolution and the measurements of the broad $2s$ excitation resonances directly showed their natural widths. Contributions of direct photo double ionization (PDI) to the production of the highest final Ar ion charge states are revealed, with PDI of the $2s$ subshell being mainly responsible for the production of ${\mathrm{Ar}}^{7+}$. The experiment made use of the PIPE setup installed at beamline P04 of the PETRA III synchrotron light source of DESY in Hamburg. The measurements were supported by theoretical calculations to identify the main contributions to the observed cross sections. Comparisons of theory and experiment show remarkable agreement but also hint to additional ionization mechanisms that are not considered in the theoretical models such as core ionization accompanied by excitations with subsequent Auger decays leading to net $m$-fold ionization with $m\ensuremath{\ge}4$.

The cadmium L x-ray spectrum induced by electron impact was analyzed in detail. The measurements were performed on a bulk pure sample using a commercial wavelength dispersive spectrometer, and the spectrum was processed with a parameter optimization method previously developed. This procedure permitted the determination of characteristic energies, relative transition probabilities and natural linewidths for this element. The results obtained here were compared to the data found in the literature, when available. Spectral structures related to satellite and radiative Auger Effect emissions were also analyzed, assessing energy shifts and relative intensities. Some of these parameters were determined for the first time, even in overlapping peaks and weak transitions, which was possible due to the robustness of the spectral processing method used.

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.

Ar divergent gas-puff ${Z}$ -pinch discharge with reversed polarity was performed. Spectroscopic and spatial properties of K-shell and L-shell radiations emitted from highly ionized Ar ions were investigated. It was confirmed that L-shell radiation was spreading in the axial direction, whereas K-shell radiation was emitted from a small spot. The spot size of K-shell radiation was measured, and the diameter of the spot was $34 \pm 9~\mu \text{m}$ . Small creatures were observed using the K-shell radiation emitted from the spot. Repetitive and intense point radiation source with limited spectrum was realized by the divergent gas-puff ${Z}$ -pinch.

Polychromatic L-shell X-ray fluorescence computed tomography is a promising imaging technique to explore the element distribution of the sample. However, the image quality of large samples would be...

Successful co-implementation of different heavy ion beam nuclear analytical techniques such as heavy ion PIXE, ERDA, MeV SIMS and RBS hinges on the availability of accurate databases of fundamental ion beam-matter interaction parameters. We report on measurements carried out to determine L-shell X-ray production cross sections in 101Ru and 181Ta due to 12C, 16O and 28Si projectile ions in the 0.2 MeV/u–1.0 MeV/u energy range. Experimental data is compared to calculations by one of the most widely implemented X-ray ionisation theories in PIXE analyses – the ECPSSR theory in its modified United Atom (UA) version. Results show fairly good agreement between experiment and theory for the 181Ta target atoms, with the level of agreement improving as the Zion/Ztarget ratio decreases and as beam energy increases. For 101Ru target atoms theoretical predictions tend to underestimate experimental data and the discrepancies increase with projectile mass and decreasing energy. The contribution of projectile electron capture (EC) to the measured X-ray production cross sections is also considered in the data analysis and discussion.

Total L and Li subshell X-ray production cross-sections were determined experimentally for Mo by proton impact. The thick-target method was used, and the proton energies ranged from 200 keV to 3 MeV. The recorded X-ray spectra were fitted using novel open software for PIXE semi-quantitative analysis that takes into account X-ray emission, absorption and detection. K-shell X-ray production cross-sections of Ti and Cu samples were used to normalize our results for Mo. The measured Mo L X-ray production cross-sections are in excellent agreement with the predictions of the ECPSSR theory. The sensitivity of the theoretical L shell and Li subshell X-ray production cross-sections to the adopted fluorescence yields and Coster-Kronig coefficients was also studied. Fil: Pérez, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina Fil: Rodríguez, Tabatha P.. Universidad Tecnológica Metropolitana; Chile Fil: Trincavelli, Jorge Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; Argentina Fil: Fernandez Varea, Jose M.. Universidad de Barcelona; España Fil: Suarez, Sergio Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina

We describe the recent inclusion in Geant4 of state-of-the-art proton and alpha particle shell ionisation cross sections based on the ECPSSR approach as calculated by Cohen et al., called here ANSTO ECPSSR. The new ionisation cross sections have been integrated into Geant4. We present a comparison of the fluorescence X-ray spectra generated by the ANSTO ECPSSR set of cross sections and, alternatively, the currently available sets of Geant4 PIXE cross sections. The comparisons are performed for a large set of sample materials spanning a broad range of atomic numbers. The two alternative PIXE cross sections approaches (Geant4 and ANSTO) have been compared to existing experimental measurements performed at ANSTO with gold, tantalum and cerium targets of interest for nanomedicine applications. The results show that, while the alternative approaches produce equivalent results for vacancies generated in the K and L shell, differences are evident in the case of M shell vacancies. This work represents the next step in the effort to improve the Geant4 modelling of the atomic relaxation and provide recommended approaches to the Geant4 user community. This new Geant4 development is of interest for applications spanning from life and space to environmental science.

L-shell ionisation and x-ray production cross sections of trans-uranium elements: Np, Pu and Am, induced by protons of energies 5.00–20.00 MeV, have been calculated. The cross sections for the targets were obtained using computer codes based on the ECPSSR theory. Due to the lack of experimental data of the targets considered, in view of their radioactive, toxic and unstable nature, the calculated cross sections were subsequently validated. This was achieved using the computer codes to evaluate the ionisation and x-ray production cross sections of Uranium induced by protons of energies in the 1.00–20.00 MeV range. This study also showed that the relative x-ray line intensities associated with the ionisation and x-ray productions of the targets considered are dependent on protons energies.

Purpose This work proposes a semiempirical correction method for attenuation of x-ray fluorescence (XRF) photons and/or an excitation beam during direct XRF imaging (i.e., mapping) of gold nanoparticle (GNP) distribution utilizing gold L-shell XRF photons. Methods The current method was first devised by finding the two following relationships: (a) ratio of gold XRF peak intensity (Lα at ~9.7 keV and Lβ at ~11.4 keV) vs pathlength of XRF photons; (b) XRF photon counts produced (Nxrf ) vs scattered photon counts produced (Nscat ). Monte Carlo simulations were performed using the Geant4 tool kit to characterize the aforementioned relationships for different tissue-like media. The applicability of the method was tested experimentally by acquiring 2D L-shell XRF images of custom-made phantoms using an experimental benchtop x-ray fluorescence computed tomography setup. Results The results show that the ratio of gold L-shell XRF peak intensities allowed an estimation of the pathlength of XRF photons, thus can be utilized to correct for attenuation of XRF photons after emission. The results also demonstrate that Nscat , through a proportionality N xrf ∝ N scat T where the exponent T depends on the energy of scattered photons, could be used to correct for attenuation of an excitation beam prior to producing XRF photons. The corrected XRF signal was found independent of the densities of tissue-like media present along the passage of an excitation beam or emitted XRF photons. Conclusions The current results suggest that the developed attenuation correction method plays an essential role for the detection of GNPs on the order of parts-per-million, and also for the determination of GNP concentration/location within the imaging object made of tissue-like media, without any prior knowledge of the imaging object shape, under the conditions deemed relevant to biomedical applications of gold L-shell XRF-based imaging.

The $LMM$ Auger spectra of krypton are measured using the photon energies $h\ensuremath{\nu}=1709$ eV, 1792 eV, 1950 eV, and 13 keV. This approach allows separating the contributions from the various core holes ${L}_{1}, {L}_{2}$, and ${L}_{3}$. Previously unobserved transitions are presented. Complementary theoretical work is performed allowing the assignment of the spectral features. The ${L}_{2,3}Y\text{\ensuremath{-}}MMY$ ($Y={M}_{4,5},{N}_{1,2,3})$ Auger transitions of ${\mathrm{Kr}}^{2+}$ formed via Coster-Kronig Auger decay of the core holes ${L}_{1}$ and ${L}_{2}$ are also investigated. These spectra comprise about 4000 and 13 000 transitions, respectively, so that only general statements on the assignment, such as the configurations involved in the transitions, can be given.

Matrix effects on the intensity of characteristic L X-rays were investigated for X-ray fluorescence (XRF). Lead was selected to be the analyte and samples were prepared with powders of several elements. In XRF analysis, if the sample analyzed is a composite, the emitted characteristic X-rays of an element can be enhanced or weakened by emission from other elements. The weight fraction of Pb and accompanying element in the matrices prepared as tablets of PbCCu1-C, PbCZn1-C, PbCMo1-C and PbCCd1-C by powder metallurgy using pure powders were varied from 10% to 90% with 10% intervals. The K shell absorption edge of Cu and Zn is just below the characteristic L X-ray energies of Pb. However, Mo and Cd emits K X-rays with energies just above the L shell absorption edge of Pb when stimulated by primary photons. All samples were analyzed by XRF using a Si(Li) detector with good resolution and an Am-241 radioactive source to provide characteristic X-ray spectra. The intensities for Lα, Lβ, and Lγ X-rays were plotted as a function of the Pb concentration and the results were evaluated to characterize matrix enhancement and absorption upon L-shell X-rays.

Two-dimensional hybrid particle-in-cell (PIC) simulations are carried out on a constant L-shell (or drift shell) surface of the dipole magnetic field to investigate the generation process of near-e...

In the Earth’s inner magnetosphere, there exist regions like plasmasphere, ring current, and radiation belts, where the population of charged particles trapped along the magnetic field lines is more. These particles keep performing gyration, bounce and drift motions until they enter the loss cone and get precipitated to the neutral atmosphere. Theoretically, the mirror point latitude of a particle performing bounce motion is decided only by its equatorial pitch angle. This theoretical manifestation is based on the conservation of the first adiabatic invariant, which assumes that the magnetic field varies slowly relative to the gyro-period and gyro-radius. However, the effects of gyro-motion cannot be neglected when gyro-period and gyro-radius are large. In such a scenario, the theoretically estimated mirror point latitudes of electrons are likely to be in agreement with the actual trajectories due to their small gyro-radius. Nevertheless, for protons and other heavier charged particles like oxygen, the gyro-radius is relatively large, and the actual latitude of the mirror point may not be the same as estimated from the theory. In this context, we have carried out test particle simulations and found that the L-shell, energy, and gyro-phase of the particles do affect their mirror points. Our simulations demonstrate that the existing theoretical expression sometimes overestimates or underestimates the magnetic mirror point latitude depending on the value of L-shell, energy and gyro-phase due to underlying guiding centre approximation. For heavier particles like proton and oxygen, the location of the mirror point obtained from the simulation deviates considerably (∼ 10°–16°) from their theoretical values when energy and L-shell of the particle are higher. Furthermore, the simulations show that the particles with lower equatorial pitch angles have their mirror points inside the high or mid-latitude ionosphere.

We present results from {\it XMM-Newton/RGS} observations of prominent knots in the southest portion of Tycho's supernova remnant, known to be the remnant of a Type Ia SN in 1572 C.E. By dispersing the photons from these knots out of the remnant with very little emission in front of or behind them, we obtained the nearly uncontaminated spectra of the knots. In the southernmost knot, the RGS successfully resolved numerous emission lines from Si, Ne, O He$\alpha$ and Ly$\alpha$, and Fe L-shell. This is the first clear detection of O lines in Tycho's SNR. Line broadening was measured to be $\sim 3$ eV for the O He$\alpha$ and $\sim 4.5$ eV for Fe L lines. If we attribute the broadening to pure thermal Doppler effects, then we obtain kT$_{O}$ and kT$_{Fe}$ to be $\sim 400$ keV and 1.5 MeV, respectively. These temperatures can be explained by heating in a reverse shock with a shock velocity of $\sim 3500$ km s$^{-1}$. The abundances obtained from fitting the RGS and MOS data together imply substantially elevated amounts of these materials, confirming previous studies that the knots are heated by a reverse shock, and thus contain ejecta material from the supernova. We are unable to find a Type Ia explosion model that reproduces these abundances, but this is likely the result of this knot being too small to extrapolate to the entire remnant., Comment: Accepted by ApJ Letters

The energies and rates of Kα X-ray satellites due to 1s − 2p transitions in iodine and gold with one to multiple vacancies in the L shell are computed using Multi-Configuration Dirac Fock wavefunctions with the inclusion of relativistic and quantum electrodynamics corrections. The calculations have been carried out for I1+ to I6+ with spectator vacancies in the 2p shell and Au1+ to Au8+ with filled and empty 2s shell along with vacancies in the 2p shell. As existing data on the X-ray emission from low ionized iodine and gold are confined to single inner shell vacancy, direct comparison of the present results on the various radiative transitions from iodine and gold with a single vacancy in the K shell, variously ionized L shell and no vacancy in any other shells is possible only for the two well known Kα 1 and Kα 2 diagram lines. Hence to substantiate the reliability of the current results through one to one comparison with existing data on the 1s − 2p transitions, calculations have also been performed on the radiative decay of H-, He-, Be-, and F-like gold with singly ionized 1s , closed 2s , multiply ionized 2p and rest of the shells open for which semi-relativistic data exist. In addition to providing additional check on the reliability of the computed results, this comparison also tries to analyze the impact of higher order relativistic corrections on the K X-ray energies and rates. The intrinsic variations of transition properties with degree of ionization have been analyzed.

We present a theoretical and experimental study of the subshell resolved L-shell ionization of relativistic targets such as 73Ta, 78Pt,90Th, and 92U. The measurements of x-ray production cross sections by (84?140 MeV) Si+q ions (q = 8; 12), were held at the Inter-University Accelerator Centre of New Delhi. Multiple-hole fluorescence and Coster-Kronig yields were used to obtain the Li(i = 1?3)ionization cross sections from the measured x-ray production cross sections of Lℓ, Lα, and Lβ, Lη, and Lγ lines. The experimental results are compared with ab initio theoretical calculations by means of the shell-wise local plasma approximation (SLPA). This model uses the quantum dielectric formalism to obtain the total ionization cross sections from an initial ground state. The wave functions and binding energies of the different targets were obtained by solving the fully-relativistic Dirac equation using the HULLAC code package. These calculations are based on first-order perturbation theory with a central field, including Breit interaction and quantum electrodynamics corrections. The present SLPA ionization cross sections of the L-shell are found to be independent of the charge state of the Si ions. The experimental observations display also quite similar character if the correct mean projectile charge state inside the target is used for including the multiple ionization effect during ion-solid collisions. A general good agreement between the experimental measurements and full theoretical calculations supports the reliability of present results. The comparison also includes the well-known ECPSSR and ECUSAR semi empirical approximations. We noted that the ECUSAR results agree well with the SLPA, while the ECPSSR cross sections are rather low. Fil: Oswal, M.. Dev Samaj College; India. Panjab University; India Fil: Kumar, Sunil. Panjab University; India. Degree college; India Fil: Singh, Udai. Jagiellonian University; Polonia Fil: Singh, G.. Panjab University; India Fil: Singh, K.P.. Panjab University; India Fil: Mehta, D.. Panjab University; India Fil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Mitra, D.. Kalyani University; India Fil: Nandi, T.. Inter-University Accelerator Centre; India

WOS: 000514219200002, In this paper, we present a compilation of the measured photon-induced K-beta/K-alpha intensity ratio values published in the literature from 1969 to 2018. In the considered period, we found about 1118 values (127 papers) for elements with 11

WOS: 000519335200007 K-alpha, K-beta and total K X-ray fluorescence cross-sections, K shell fluorescence yields, K-beta/K-alpha X-ray intensity ratios, K to L shell vacancy transfer probabilities and Auger electrons emission ratios of some selected Mn and Ni compounds have been investigated. The measurements were carried out by using Am-241 radioactive source and high-resolution Si(Li) detector. The measured results were compared with other experimental values and theoretical calculations. Our values are in good concordance with calculated theoretical and other experimental values.

We have used the Shenguang II laser in third harmonic (351 nm) to investigate the emission of L-shell radiation in the 3.3 to 4.4 keV range generated using thin foils of Sn coated onto a parylene substrate with irradiation of order 1015 Wcm−2 and nanosecond pulse duration. In our experiment, we have concentrated on assessing the emission on the non-laser irradiated side as this allows an experimental geometry relevant to experiments on photo-ionised plasmas where a secondary target must be placed close to the source, to achieve X-ray fluxes appropriate to astrophysical objects. Overall L-shell conversion efficiencies are estimated to be of order 1%, with little dependence on Sn thickness between 400 and 800 nm.

The ionization and X-ray production cross section are fundamental parameters in elemental analysis by PIXE technique. Unfortunately no exact general analytical expression exists, from which the interest of this work. In this paper, we apply the neural network technique in the evaluation of the X-ray production cross sections. The calculations are based on Mukoyama’s PWBA data. Our results are compared with experimental data for protons and alpha particles for energies ranging from hundreds KeV to tens MeV.