Cross-sectional X-ray Research Articles

Simulation Calculation of Element Number Density in the Earth’s Atmosphere Based on X-ray Occultation Sounding

The number density profiles of elements N and O in the altitude range of 120–250 km are retrieved by simulation based on X-ray occultation. Based on the parameters of the NICER telescope, the energy spectrum forward model of the Crab Nebula in the energy range of 0.25–8 keV during the occultation is constructed, and the energy spectrum simulation data are obtained by adding noise to the energy spectrum forward model at different tangent point altitudes. The NICER energy band includes the K-shell absorption edges (0.4 keV, 0.53 keV for N, O), and there are significant differences in X-ray cross sections at the K-shell absorption edges, which provides an opportunity to retrieve the atmospheric density of each element. The MCMC algorithm is used to fit the energy spectrum forward model and simulation data, and the density profiles of elements N and O are retrieved. It is found that the retrieved error of O element in the altitude range of 120–140 km is large, which may be related to the low proportion of O in the line of sight and the low signal-to-noise ratio of simulation data. In the altitude range of 140–200 km, the retrieved error of elements N and O is small, but in the altitude range of 200–250 km, the retrieved error of elements N and O becomes larger, and the inconsistency between the retrieved results and NRLMSISE-00 model values increases. This is because the number of absorbed photons is reduced due to the thin atmospheric density at higher altitude, which introduces great uncertainty into the retrieved results. This study lays a foundation for element density retrieval based on X-ray occultation measured data in the future.

Effects of process parameters on structure and corrosion behavior of PEO coated A356 alloy

Plasma electrolytic oxidation (PEO) coatings were formed on cast A356 aluminum alloy by applying various process parameters (current density, duty cycle and processing time) in silicate based electrolyte. The phase composition of coatings was analyzed by x-ray diffraction (XRD), surface and cross section morphology and microstructure of coatings were characterized by scanning electron microscope (SEM). The Results of x-ray diffraction showed that all coatings are composed of gamma alumina. Coating produced in higher current density, duty cycle and time was more compact with fewer amounts of defects. Thickness and roughness of coatings surfaces were measured by Eddy current gauge and surface roughness tester, respectively. The thickness of the Coatings was in the range of 3–7 μm and it increased by increasing current density and time, but duty cycle did not have a noticeable effect on it. Corrosion resistance of bare and coated samples was evaluated by polarization test in 3.5 wt% NaCl solution. Sample S176 showed the best corrosion resistance with corrosion current density of 4.17 × 10−8 A.cm−2 and polarization resistance of 6.31 × 105 Ω.cm2 that attributed to its more dense structure.

Total Cross Section Phenomenological Formulas for X-Ray and Gamma Radiation Interaction With Matter for Different Energies and Absorber Types

Abstract The in-function log-polynomial regression method for empirical approximations of physical relationships was presented and applied in practice. Thanks to that the single phenomenological equation for the total cross section for X-ray and gamma radiation interaction with matter was presented. The proposed equation depends on the photon energy (from 1 keV to 100 GeV) and absorber type (atomic number from Z = 1 to 100) and takes into considerations all important physical effects of photon interaction, namely, coherent (Rayleigh) and incoherent (Compton) scattering, photo-electric effect and pair/triplet production. Finally, the single formula for the total cross section of photon interaction with matter was presented in the simple form easy to apply in practice, e.g., in radiation protection or in radiation shields designing.

Phase Formation and High-Temperature Stability of Very Thin Co-Sputtered Ti-Al and Multilayered Ti/Al Films on Thermally Oxidized Si Substrates.

Ti-Al thin films with a thickness of 200 nm were prepared either by co-sputtering from elemental Ti and Al targets or as Ti/Al multilayers with 10 and 20 nm individual layer thickness on thermally oxidized Si substrates. Some of the films were covered with a 20-nm-thick SiO layer, which was used as an oxidation protection against the ambient atmosphere. The films were annealed at up to 800 °C in high vacuum for 10 h, and the phase formation as well as the film architecture was analyzed by X-ray diffraction, cross section, and transmission electron microscopy, as well as Auger electron and X-ray photoelectron spectroscopy. The results reveal that the co-sputtered films remained amorphous after annealing at 600 °C independent on the presence of the SiO cover layer. In contrast to this, the -TiAl phase was formed in the multilayer films at this temperature. After annealing at 800 °C, all films were degraded completely despite the presence of the cover layer. In addition, a strong chemical reaction between the Ti and SiO of the cover layer and the substrate took place, resulting in the formation of Ti silicide. In the multilayer samples, this reaction already started at 600 °C.

LMD coatings as filler material for laser beam welded 30 mm thick plates

The development of high energy laser sources enables single-pass welds of thick plates up to 30 mm, but often additional materials are needed to influence the properties of the weld seams. However, the homogenous distribution of filler materials in form of e.g. electrodes is only possible up to 7 mm while the elements are only traceable up to a depth of 14 mm. To overcome this problem a two-step process is used where first the edges of the weld partners are coated with the filler material by laser metal deposition (LMD) and afterwards are welded by laser beam. Single-pass welds with electromagnetic weld pool support of 30 mm thick S355 J2+N-plates with austenitic AISI 316L-coatings were investigated as well as the influence of the coatings to the penetration depth of the laser beam without electromagnetic weld pool support in double-sided joints. The weld seams were tested by X-ray inspection and cross sections.

Characteristic X-ray yields and cross sections of thick targets of Al, Ti, Zr, W and Au induced by keV-electron impact

In this paper, pure thick Al (Z = 13), Ti (Z = 22), Zr (Z = 40), W (Z = 74) and Au (Z = 79) targets are bombarded by electrons in an energy range of 5–27 keV, and the experimental thick-target characteristic X-ray yields of K-shell and L-shell, the X-ray production cross sections and the ionization cross sections of inner shells are presented. The present experimental setup and data processing are improved, specifically, a deflection magnet is installed in front of the X-ray detector to prevent the backscattered electron from entering into the X-ray detector, and the bremsstrahlung background spectra calculated from PENELOPE Monte Carlo simulations are used to deduce the net peak areas. The X-ray detector used in this experiment is the XR-100SDD manufactured by Amptek Inc. with a 25 mm<sup>2</sup> C2 ultra-thin window which can detect the low-energy x-rays down to boron Kα line (0.183 keV). Standard sources (<sup>55</sup>Fe, <sup>57</sup>Co, <sup>137</sup>Cs and <sup>241</sup>Am) with an activity accuracy range of 1%–3% (<i>k</i> = 2), supplied by the Physikalisch-Technische Bundesanstalt, Germany (PTB), are used to perform the detector’s efficiency calibration, and in a low-energy range (< 3.3 keV) the efficiency calibration is accomplished by measuring characteristic X-ray spectra produced by 20 keV electron impacting various thickness solid targets (i.e. by the characteristic peak method). The uncertainty of the detector’s efficiency calibration obtained in this paper is ~1.6%. The experimental thick-target characteristic X-ray yield data with an uncertainty of 1.7%–6.2% are compared with the PENELOPE Monte Carlo simulations, in which the inner-shell ionization cross sections are based on the distorted-wave Born approximation (DWBA) calculations, and they are in good agreement with a difference of less than or ~10%. According to the measured thick-target characteristic x-ray yields, the K-shell ionization cross sections for Al, Ti and Zr and the L-shell X-ray production cross sections for Zr, W and Au are also obtained with an uncertainty of 5%–8% (except for Al due to large K-shell fluorescence yield uncertainty), the difference between the experimental and theoretical data is also less than or ~10%. Moreover, by comparing the thick-target characteristic X-ray yields obtained from the analytical model and the PENELOPE Monte Carlo simulations at the electrons’ incident angles of 45° and 90°, it is found that the degree of agreement between the results from the analytical model and the Monte Carlo simulations at the incident angle of 90° is better than at the incident angle of 45°. Moreover, the contributions of the secondary electrons and bremsstrahlung photons to the characteristic X-ray yield are also given based on the PENELOPE Monte Carlo simulations. As for the elements studied in this paper, for the low ionization threshold energy, the contribution of the secondary electrons is ~2%, and however, for the high ionization threshold energy, the contribution is ~10%–20%. These contributions depend weakly on the energy of the incident electrons and show that these contributions are closely correlated with atomic number.

Method to Extract System-Independent Material Properties From Dual-Energy X-Ray CT

In 2016, we published a method for processing dual-energy computed tomography (DECT) data called system-independent rho-e/Z-e ( $\rho _{\mathrm {e}}/Z_{\mathrm {e}}$ ) or SIRZ. Using data from multiple DECT systems and spectra, SIRZ estimated the electron density $\rho _{\mathrm {e}}$ and effective atomic number $Z_{\mathrm {e}}$ (based on published X-ray cross sections), for a set of known specimens. However, the decomposition process required complex spectral modeling of the DECT system, which made SIRZ difficult to implement and automate. This paper describes the subsequent work on “SIRZ-2” to simplify the spectral modeling, automate the process, and improve its range and versatility. The SIRZ-2 basis functions are more accurate for the X-ray energy range ( $Z_{\mathrm {e}}$ of 6–20) were scanned with multiple spectral pairs (up to 200 keV) on seven different DECT systems, including a commercial airport luggage scanner. For these varied tests, the average SIRZ-2 relative errors for $\rho _{\mathrm {e}}$ estimates were four times lower (0.7% compared to 3.0% for SIRZ), while average $Z_{\mathrm {e}}$ relative errors were comparably low for both methods ( $\rho _{\mathrm {e}}$ , $Z_{\mathrm {e}}$ ) that can be directly compared across DECT systems and over time.

Insights into fractures and minerals in subbituminous and bituminous coals by FESEM-EDS and X-ray μ-CT

Fractures are the main pathways for fluid transport, which constrain the coalbed methane (CBM) reservoir permeability. Permeability is one of the key petrophysical parameters for CBM production. The fractures in the low and middle rank coals usually filled with minerals, which can significantly reduce the reservoir permeability. In this study, X-ray μ-CT combined with field emission scanning electron microscopy (FESEM) together with energy dispersive spectrometry (EDS) were used to quantitatively evaluate the features of fractures and minerals of FK sample (Ro,max 0.65%) and ML sample (Ro,max 1.49%) including morphology, complexity, volume and 3D structure, and its impacts on permeability. The results showed that fractures are well developed as observed in the samples FK and ML by the 2D cross section of X-ray μ-CT. Dolomite and kaolinite are common in the samples FK and ML as confirmed by FESEM images with EDS. Moreover, the 3D fracture structure including the open fracture and mineral filled fracture were reconstructed. The quantitative structural parameters (e.g. length, width, area and volume) of the fractures for these two samples were acquired by the commercial software Avizo 9.0.1. The middle rank coal of sample ML has larger fracture density (181 fractures per mm3) than that of the low rank coal of sample FK (104 fractures per mm3). Based on the reconstructed 2D and 3D fracture structure, the fracture complexity was evaluated through fractal dimension. And the impacts of mineralization in coals on petrophysical properties were evaluated, which show that the connectivity of fractures, porosity and permeability were greatly improved after demineralization. Therefore, this study may have implications for enhanced CBM recovery through demineralization.

Heavy ion PIXE cross sections in Ti, Zn, Nb, Ru and Ta for 4.8–30.0 MeV oxygen and 3.0–12.0 MeV lithium beams

Heavy ion Particle Induced X-ray Emission (PIXE) spectroscopy offers a number of advantages over standard proton PIXE, such as higher yields and therefore higher sensitivity. However, in order to be able to use heavy ion PIXE more detailed measurements of the ionisation and X-ray cross sections for heavy ions are required. This issue was recognised by one of the Coordinated Research Projects (CRP) of the IAEA on MeV Secondary Ion Mass Spectrometry (SIMS). ANSTO took part in this CRP and we measured X-ray production cross sections on a range of samples for oxygen and lithium beam in the energy range of 4.8–30 MeV and 3–12 MeV, respectively. Here we report on these X-ray production cross section measurements and compare the results with theoretical models. Further energy shifts of the characteristic X-ray lines for the different ion-target combinations are presented and discussed.

Resonant Inelastic X-ray Scattering Amplitudes and Cross Sections in the Algebraic Diagrammatic Construction/Intermediate State Representation (ADC/ISR) Approach.

A scheme has been derived and implemented to gain computational access to the full electronic part of the Kramers-Heisenberg-Dirac (KHD) expression for resonant and nonresonant inelastic scattering amplitudes. Our implementation of this scheme is based on the complex polarization propagator in the algebraic diagrammatic construction (ADC) framework and within its intermediate state representation (ISR). The hierarchy of the second- and third-order ADC/ISR computational schemes known as ADC(2), ADC(2)-x, and ADC(3/2) is considered, and the calculated resonant inelastic X-ray scattering (RIXS) amplitudes and transition strengths for water are in excellent agreement with recent experimental data.

Multiferroic YCrO3 thin films: Structural, ferroelectric and magnetic properties

Abstract Highly oriented and locally epitaxial multiferroic YCrO3 (001) thin films, 20 nm thick, were deposited by r.f. magnetron sputtering on SrTiO3 (110) substrates at 890 °C. The structure was investigated by x-ray diffraction and cross section high resolution transmition electron microscopy, a clear local matching between the YCrO3 film and the substrate was observed. Ferroelectricity was confirmed by means of switching areas with opposite polarization directions, first and second harmonic electromechanical signals, and local hysteresis ferroelectric curves obtained by piezoresponse force microscopy. Additionally, below the Neel temperature, a clear ferromagnetic hysteresis loop was observed. These results will encourage further studies on the mechanism that promotes the ferroelectric nature in YCrO3 compound.

System-Independent Characterization of Materials Using Dual-Energy Computed Tomography

We present a new decomposition approach for dual-energy computed tomography (DECT) called SIRZ that provides precise and accurate material description, independent of the scanner, over diagnostic energy ranges (30 to 200 keV). System independence is achieved by explicitly including a scanner-specific spectral description in the decomposition method, and a new X-ray-relevant feature space. The feature space consists of electron density, ${\rho _{\rm e}}$ , and a new effective atomic number, ${{\rm Z}_{\rm e}}$ , which is based on published X-ray cross sections. Reference materials are used in conjunction with the system spectral response so that additional beam-hardening correction is not necessary. The technique is tested against other methods on DECT data of known specimens scanned by diverse spectra and systems. Uncertainties in accuracy and precision are less than 3% and 2% respectively for the ( ${\rho _{\rm e}}$ , ${{\rm Z}_{\rm e}}$ ) results compared to prior methods that are inaccurate and imprecise (over 9%).

Influence of working gas properties on MWPC anode wire modulation effect**Supported by Scientific Research Fund of Sichuan Provincial Education Department (11ZA140)

For MWPCs used for X-ray position detection, simulation studies of the anode wire modulation effect of the detector were carried out using the Garfield program. Different gas mixtures were used as the working gas in the simulation, so as to obtain the influence of the X-ray cross section and electron diffusion coefficient of the working gases on the anode wire modulation effect of an MWPC with anode wire spacing of 2 mm. Results show that, though a working gas with higher X-ray cross section implies a larger average drift distance for the ionized electrons, such gas mixtures are of little use in improving the anode wire modulation effect of MWPCs. It is found that the transverse electron diffusion coefficient is the determining factor for the extent of the anode wire modulation effect in the detector.

Analysis of quality hdmi connector component welding in mother board laptop

The paper aims to assess the quality of HDMI connector component of welding in the welding process laptop printed circuit board meeting the eligibility criteria related to the filling of the solder barrel to pin through-hole components terminals as specified in international standard IPC-A-610D. For the development of the stages of research, it adopted the PDCA method, used for troubles hooting and application of continuous improvement, commonly used by different companies in the industrial segment worldwide. The results presented through analysis by X-RAY and metallographic test cross section, showed that the quality of HDMI welding through the automatic welding process by remelting meets the technical specifications of the standard of acceptability. Thus, left to perform the welding of this type of component in the manual process, passing it to weld using SMT technology.

M X-ray cross sections from 75 to 300 keV proton bombardment of selected 5d transition elements

M X-ray production cross sections for selected thick targets of Hf, W, Re, Pt, Au and Pb impacted by 75–300keV protons are presented and compared with ECPSSR and RPWBA theories using different atomic data bases, including comparisons with other investigators. The results for the major M X-ray transitions exhibit a universal character with respect to the reduced proton velocity in agreement with expectations from theory.

Configuration of the posterior lumbar muscles regarding the study of the lumbosacral malformations

Purpose: A correlation between the shape of the three posterior lumbar muscles (Multifidus, Longissimus pars lumborum and Iliocostalis pars lumborum) and the vertebrae levels has been studied with regards to lumbosacral malformations and the extraforaminal approach (ELIF). Material and method: During a spine unit consultation, a series of 90 lumbar spines have been studied with X-ray and CT axial horizontal cross sections thanks to a special software. At every level, the ratio between the surface of the Multifidus and the global surface of the 3 posterior lumbar muscles was calculated. Among the 90 studied lumbar spines, 59 presented a normal bony frame while 31 were supposed to have a lumbosacral malformation. Results: For L5S1, L4L5, L3L4, L2L3 the normal ratio are respectively 95%, 51%, 34% and 18%. Any changes in these patterns may call forth a sacralization with two different forms, depending on the number (four or five) of the so-called “lumbar vertebrae”. Conclusion: The muscle patterns lead the clinician to study the lumbosacral malformation, and the surgeon to undergo the extraforaminal intermuscular discal surgery. Purpose: A correlation between the shape of the three posterior lumbar muscles (Multifidus, Longissimus pars lumborum and Iliocostalis pars lumborum) and the vertebrae levels has been studied with regards to lumbosacral malformations and the extraforaminal approach (ELIF). Material and method: During a spine unit consultation, a series of 90 lumbar spines have been studied with X-ray and CT axial horizontal cross sections thanks to a special software. At every level, the ratio between the surface of the Multifidus and the global surface of the 3 posterior lumbar muscles was calculated. Among the 90 studied lumbar spines, 59 presented a normal bony frame while 31 were supposed to have a lumbosacral malformation. Results: For L5S1, L4L5, L3L4, L2L3 the normal ratio are respectively 95%, 51%, 34% and 18%. Any changes in these patterns may call forth a sacralization with two different forms, depending on the number (four or five) of the so-called “lumbar vertebrae”. Conclusion: The muscle patterns lead the clinician to study the lumbosacral malformation, and the surgeon to undergo the extraforaminal intermuscular discal surgery.

Effective collision cross section of xenon plasma debris in argon buffer gas

Mitigation of fast debris and soft x-rays generated from laser-produced xenon plasmas were studied in an argon buffer gas in laser intensities of 109–1011 W cm−2 using a cryogenic drum target. Considerable mitigation of debris was confirmed by measurements of material sputtering. From the experimental results, an attenuation parameter of sputtering by the debris and an absorption cross section of soft x-rays at 13.5 nm σ2(13.5 nm) were derived to be 2.2 × 10−20 m2 and 1.8 × 10−22 m2, respectively. Moreover, is concluded to be equivalent to the effective collision cross section σ1 of a debris particle at kinetic energy of 1–4 keV. Sufficient debris mitigation can be obtained together with low soft x-ray absorption (less than 10%). These parameters provide a useful design tool for realizing a practical soft x-ray source because they predict the effect of the buffer gas well.

Determination of effective atomic number and electron density of chitin by gamma-ray attenuation

The effective atomic numbers (Zeff) and effective electron density (Ne) of chitin have been calculated using the mass attenuation coefficients (m/r) obtained via XCOM (COMpilation of X-ray Cross Sections) in the photon energy range between 1 keV and 1 GeV. The results were compared with the measured values at the photon energy of 662, 1173 and 1332 keV. Both measured and calculated results were in good agreement. Key words: Effective atomic number, chitin, effective electron number, COMpilation of X-ray Cross Sections (XCOM).

FIB Induced X-rays (FIBIX) Using 30 keV Ga+ Ions

FIB induced X-rays (FIBIX) using a 30 keV Ga+ primary ion beam were collecting using EDS and WDS techniques for conducting samples, YBCO, Al, Cu, ZrB2, and Mo. FIBIX X-ray cross sections are largest for the light element materials, presumably due to momentum transfer from the primary ions to the target atoms and consistent with molecular orbital generation processes. The Ga+ Bremsstrahlung is largest in the low energy X-ray range, less than ∼1 keV, but is essentially nonexistent at higher energies. Thus, characteristic X-ray peaks greater than ∼1 keV are easily identifiable and statistically significant even at low count rates. The large FIBIX counts observed at less than 1 keV are a combination of Bremstrahhlung and characteristic low energy X-rays from light elements, as confirmed by high energy resolution WDS measurements. Low energy X-rays from heavy element targets are difficult to detect using FIBIX, again presumably due to a small amount of momentum transfer to the target atoms.

Formation of Si/SiC multilayers by low-energy ion implantation and thermal annealing

Si/SiC multilayer systems for XUV reflection optics with a periodicity of 10–20 nm were produced by sequential deposition of Si and implantation of 1 keV View the MathML source ions. Only about 3% of the implanted carbon was transferred into the SiC, with a thin, 0.5–1 nm, buried SiC layer being formed. We investigated the effect of thermal annealing on further completion of the carbide layer. For the annealing we used a vacuum furnace, a rapid thermal annealing system in argon atmosphere, and a scanning e-beam, for different temperatures, heating rates, and annealing durations. Annealing to a temperature as low as 600 °C resulted in the formation of a 4.5 nm smooth, amorphous carbide layer in the carbon-implanted region. However, annealing at a higher temperature, 1000 °C, lead to the formation of a rough poly-crystalline carbide layer. The multilayers were characterized by grazing incidence X-ray reflectometry and cross section TEM.