scholarly journals Energy Dependency of Proton-Induced Outer-Shell Multiple Ionization for 48Cd and 49In

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xianming Zhou ◽  
Jing Wei ◽  
Rui Cheng ◽  
Yanhong Chen ◽  
Yongtao Zhao ◽  
...  
Keyword(s):  
Cross Sections ◽  
Relative Intensity ◽  
Outer Shell ◽  
Atomic Data ◽  
X Rays ◽  
X Ray ◽  
Direct Ionization ◽  
Multiple Ionization ◽  
Ionization Cross Sections ◽  
The Impact

L subshell X-rays of 48Cd and 49In have been measured for the impact of protons with energies from 75 to 250 keV. Obviously, it is found that Lγ2 (abbreviation Lγ2,3 for 48Cd and Lγ2,3,4 for 49In) X-ray emission is enhanced in comparison with Lγ1 X-ray emission. The relative intensity ratios of Lγ2 to Lγ1 X-ray are larger than the atomic data and increase with decreasing proton energy. This is caused by the multiple ionization of outer-shell electrons. To verify this explanation, the enhancements for relative intensity ratio of Lι and Lβ2 to Lα X-ray in experiments are discussed, and the direct ionization cross sections of 4d, 5s, and 5p electrons are calculated using BEA theory.

On the Peak to Background Ratio of X-Rays emitted from Rough Surfaces

2000 ◽  
Vol 6 (S2) ◽  
pp. 920-921 ◽  
Author(s):  
Raynald Gauvin ◽  
Eric Lifshin
Keyword(s):  
Cross Sections ◽  
Quantitative Method ◽  
X Rays ◽  
Beam Position ◽  
X Ray ◽  
Flat Surfaces ◽  
Background Ratio ◽  
Spherical Inclusions ◽  
Homogeneous Composition ◽  
Ionization Cross Sections

The classical schemes to convert the x-ray intensity into concentration, using the ZAF or the ϕ (ρz ) methods, are valid for specimens having homogeneous composition and flat surfaces . Quantitative schemes have also been developed for x-ray microanalysis of multi-layered specimens. More recently, a quantitative method has been proposed for the microanalysis of spherical inclusions embedded in a matrix as well as Monte Carlo simulations of x-ray emission from porous materials.For the case of specimens having a non-planar surface, a quantitative method based on the peak to background ratio, using photons of the same energy, has been proposed1. However, this method has some pitfalls. First, this method is based on the assumption that the peak to background ratio is independent of the specimen roughness which is not strictly correct because the ionization cross sections and the bremstrallung cross sections are not the same. Therefore, the shapes of the ϕ (p z ) curves are not the same for characteristic and continuum photon of the same energy resulting in different absorption corrections. The result is that the peak to background ratio will vary with beam position on a rough surface.

X-Ray Production Cross Sections for Ti, Co, Ge, Rb and Sn by 16 - 44 Mev Oxygen Ion Bombardment

1973 ◽  
Vol 17 ◽  
pp. 445-456
Author(s):  
R. F. Chaturvedi ◽  
J. L. Duggan ◽  
T. J. Gray ◽  
C. C. Sachtleben ◽  
J. Lin
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
X Rays ◽  
X Ray ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Theoretical Predictions ◽  
Ionization Cross Sections ◽  
Binary Encounter Approximation ◽  
Shell Ionization

AbstractAbsolute K-shell ionization cross sections were measured for Ti, Co, Ge, Rb, and Sn for incident oxygen ions from 16-44 MeV. The x-rays were measured with a high resolution Si(Li) detector (166 eV at 5.9 keV). All of the data represents cross section measurements for thin targets. The measured cross sections for these elements are compared to the theoretical predictions of the Binary Encounter Approximation (BEA). Kα/Kβratios and energy shifts were also extracted from the data. The experimental data are compared to measured cross sections for other elements to give an overview of the systematics for oxygen ion induced x-ray production cross sections in this energy range. Some comment will also be given in regard to the use of oxygen ions to measure the parameters associated with ion implanted semiconductors.

X-RAY PRODUCTION, INNER SHELL IONIZATION AND READING’S THEOREM IN ION · ATOM COLLISIONS

1992 ◽  
Vol 02 (03) ◽  
pp. 197-209
Author(s):  
KEIZO ISHII
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
X Rays ◽  
Ionization Cross ◽  
Heavy Charged Particles ◽  
X Ray ◽  
Inner Shell Ionization ◽  
Ionization Cross Sections ◽  
Shell Ionization

When a solid or gaseous target is bombarded with heavy charged particles, inner shell electrons of target atoms are ionized and characteristic x rays are produced. We can easily observe these x rays with a Si(Li) detector and derive inner-shell ionization cross section from the x-ray production cross sections. In this paper, we make a review of x-ray production, inner shell ionization and Reading’s theorem in light ion·atom collisions. This theorem is one of the most important ones in the ion·atom collision physics and permits precise discussion on comparison between experimental inner-shell ionization cross sections obtained with a Si(Li) detector and the calculations based on usual theories where the incident particle is assumed to interact with only one electron in an atom and the presence of other electrons is ignored.

scholarly journals Optical and Radio Information

1968 ◽  
Vol 1 ◽  
pp. 206-209
Author(s):  
Hugh M. Johnson
Keyword(s):  
Cross Sections ◽  
Supernova Remnants ◽  
Galactic Plane ◽  
Optical Data ◽  
X Rays ◽  
Interstellar Gas ◽  
X Ray ◽  
The Galaxy ◽  
Ionization Cross Sections ◽  
Optical Astronomy

The six or eight optically identified X-ray sources comprise starlike objects and extended supernova remnants in the Galaxy, well as as a radio galaxy and a quasar. Both X-ray and radiofrequency radiation penetrate the entire galactic plane, but only two or three galactic radio sources have been identified with X-ray sources. This has led Hayakawa et al. to postulate that detectable X-ray sources are not farther than 1 kpc. However, other studies suggest that there is a cluster of a few intrinsically bright sources actually near the galactic nucleus and a scattering of weaker sources near the sun.The distances of X-ray sources can be estimated from extinction by interstellar gas or intergalactic gas on spectra above 10 Å, but the method ultimately depends on the radio and optical data of the gas. Conversely, interstellar densities of certain elements with large photo-ionization cross-sections may be determined from the absorption of X-rays, after calibration of source distances by the methods of optical astronomy.

scholarly journals How do Uncertainties in Atomic Parameters Influence Theoretical Predictions of X-Ray Production Cross Sections By Proton Impact?

2020 ◽  
Vol 7 (2) ◽  
pp. 71-76
Author(s):  
J Miranda
Keyword(s):  
Cross Sections ◽  
Transition Probabilities ◽  
Production Cross ◽  
Emission Rates ◽  
X Rays ◽  
X Ray ◽  
Proton Impact ◽  
Analytical Technique ◽  
Ionization Cross Sections ◽  
Atomic Parameters

The emission of characteristic X-rays induced by proton impact is a phenomenon known since the first half of the 20th century. Its more widely known application is the analytical technique Particle Induced X-ray Emission (PIXE). Several models have been developed to calculate, first, ionization cross sections and then the subsequent X-ray production cross sections. However, to carry out the comparisons of these predictions with experimental data it is necessary to use atomic parameters databases (fluorescence yields, Coster-Kronig transition probabilities, emission rates) that also have experimental uncertainties. In this work it is demonstrated how these values do not allow to decide which model describes more accurately the cross sections, due to a final “theoretical uncertainty” obtained through the propagation of the original uncertainties.

Measurements of Electron Impact K-shell Ionization Cross Sections of Cr21+ Ions

2021 ◽  
Author(s):  
David Vogel ◽  
Peter Beiersdorfer ◽  
Keith Wong ◽  
Ron Zasadzinski ◽  
Ming Feng Gu
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
X Rays ◽  
Distorted Wave ◽  
Ionization Cross ◽  
X Ray ◽  
Relative Cross Section ◽  
Inner Shell Ionization ◽  
Ionization Cross Sections ◽  
Shell Ionization

We present relative cross section measurements of the inner-shell ionization of highly charged chromium ions by high-energy (7-30 keV) electrons. The measurements use a technique based on high-resolution x-ray spectroscopy, which correlates ionization events with K∝ decay x rays. Moreover, the measurements show that inner-shell ionization only affects the strength of the heliumlike 1s2s 3S1 -> 1s2 1S0 forbidden line. The cross sections inferred for Li-like Cr21+ agree well with distorted wave calculations.

What Remains to Be Done to Allow Quantitative X-Ray Microanalysis Performed with EDS to Become a True Characterization Technique?

2012 ◽  
Vol 18 (5) ◽  
pp. 915-940 ◽  
Author(s):  
Raynald Gauvin
Keyword(s):  
Spatial Resolution ◽  
Cross Sections ◽  
Bethe Equation ◽  
Fundamental Parameter ◽  
X Rays ◽  
Ionization Cross ◽  
X Ray ◽  
Fundamental Parameters ◽  
Characteristic Lines ◽  
Ionization Cross Sections

AbstractThis article reviews different methods used to perform quantitative X-ray microanalysis in the electron microscope and also demonstrates the urgency of measuring the fundamental parameters of X-ray generation for the development of accurate standardless quantitative methods. Using ratios of characteristic lines acquired on the same X-ray spectrum, it is shown that the Cliff and LorimerKA-Bfactor can be used in a general correction method that is appropriate for all types of specimens and electron microscopes, providing that appropriate corrections are made for X-ray absorption, fluorescence, and indirect generation. Since the fundamental parameters appear in theKA-Bfactor, only the ratio of the ionization cross sections needs to be known, not their absolute values. In this regard, the measurement of ratios of theKA-Bfactor (or intensities at different beam energies of the same material with no change of beam spreading in the material) permits the validation for the best models to compute the ratio of ionization cross sections. It is shown, using this method, that the nonrelativistic Bethe equation, to compute ionization cross section, is very close to the equation of E. Casnati et al. (J Phys B15, 155–167, 1982) and also to the equations proposed by D. Bote and F. Salvat (Phys Rev A77, 042701, 2008) for the computation of the ratio of ionization cross sections. The method is extended to show that it could be used to determine the values of the Coster-Kronig transitions factors, an important fundamental parameter for the generation of L and M lines that is mostly known with poor accuracy. The detector efficiency can be measured with specimens where their intensities were measured with an energy dispersive spectrometer detector, the efficiency of which has been measured in an X-ray synchrotron (M. Alvisi et al.,Microsc Microanal12, 406–415, 2006). The spatial resolution should always be computed when performing quantitative X-ray microanalysis and the equations of R. Gauvin (Microsc Microanal13(5), 354–357, 2007) for bulk materials and the one presented in this article for thin films should be used. The effects of X-rays generated by fast secondary electrons and by Auger electrons are reviewed, and their effect can be detrimental for the spatial resolution of materials involving low-energy X-ray lines, in certain specific conditions. Finally, quantitative X-ray microanalysis of heterogeneous materials is briefly reviewed.

Nd L-shell x-ray emission induced by light ions

2021 ◽  
Author(s):  
Xian-Ming Zhou ◽  
Jing Wei ◽  
Rui Cheng ◽  
Yan-Hong Chen ◽  
Ce-Xiang Mei ◽  
...  
Keyword(s):  
Incident Energy ◽  
Nuclear Charge ◽  
Blue Shift ◽  
Atomic Data ◽  
X Rays ◽  
X Ray ◽  
Multiple Ionization ◽  
Light Ions ◽  
Intensity Ratios ◽  
Shell Ionization

Abstract The L-shell x ray of Nd has been obtained for 300 - 600 keV He2 + ions impacting, and compared with that produced by H+ and H2 + ions. The threshold of projectile kinetic energy for L-shell ionization of Nd is crudely verified in the energy region of about 300 - 400 keV. It is found that the energy of the distinct L-subshell x rays has a blue shift. The relative intensity ratios of Lβ1, 3, 4 and Lβ2, 15 to Lα1, 2 x-ray are enlarged compared to the atomic data, and they decrease with the increase of incident energy, and increase with increasing effective nuclear charge of the incident ions. That is interpreted by the multiple ionization of outer-shells induced by light ions.

scholarly journals X-ray Shielding, Mechanical, Physical, and Water Absorption Properties of Wood/PVC Composites Containing Bismuth Oxide

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2212
Author(s):  
Worawat Poltabtim ◽  
Ekachai Wimolmala ◽  
Teerasak Markpin ◽  
Narongrit Sombatsompop ◽  
Vichai Rosarpitak ◽  
...  
Keyword(s):  
Impact Strength ◽  
Water Absorption ◽  
Attenuation Coefficient ◽  
Bismuth Oxide ◽  
Morphological Properties ◽  
Linear Attenuation Coefficient ◽  
X Rays ◽  
Equivalent Thickness ◽  
X Ray ◽  
The Impact

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.

scholarly journals Impact of aging on gene expression response to x-ray irradiation using mouse blood

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Constantinos G. Broustas ◽  
Axel J. Duval ◽  
Sally A. Amundson
Keyword(s):  
Gene Expression ◽  
Differentially Expressed Genes ◽  
Differentially Expressed ◽  
X Rays ◽  
Gene Expression Response ◽  
X Ray ◽  
The Impact ◽  
Old Mice ◽  
Radiation Biodosimetry ◽  
Young Mice

AbstractAs a radiation biodosimetry tool, gene expression profiling is being developed using mouse and human peripheral blood models. The impact of dose, dose-rate, and radiation quality has been studied with the goal of predicting radiological tissue injury. In this study, we determined the impact of aging on the gene expression profile of blood from mice exposed to radiation. Young (2 mo) and old (21 mo) male mice were irradiated with 4 Gy x-rays, total RNA was isolated from whole blood 24 h later, and subjected to whole genome microarray analysis. Pathway analysis of differentially expressed genes revealed young mice responded to x-ray exposure by significantly upregulating pathways involved in apoptosis and phagocytosis, a process that eliminates apoptotic cells and preserves tissue homeostasis. In contrast, the functional annotation of senescence was overrepresented among differentially expressed genes from irradiated old mice without enrichment of phagocytosis pathways. Pathways associated with hematologic malignancies were enriched in irradiated old mice compared with irradiated young mice. The fibroblast growth factor signaling pathway was underrepresented in older mice under basal conditions. Similarly, brain-related functions were underrepresented in unirradiated old mice. Thus, age-dependent gene expression differences should be considered when developing gene signatures for use in radiation biodosimetry.

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