THE NUCLEAR ABSORPTION OF X-RAYS BY OXYGEN

1958 ◽  
Vol 36 (7) ◽  
pp. 963-976 ◽  
Author(s):  
A. K. M. Siddiq ◽  
R. N. H. Haslam
Keyword(s):  
X Rays ◽  
Energy Response ◽  
Absorption Process ◽  
X Ray ◽  
Response Characteristics ◽  
Nuclear Absorption ◽  
Continuous Absorption ◽  
Small Absorption ◽  
Predicted Values ◽  
Experimental Values

The total X-ray attenuation ratio in water was measured as a function of energy in the region 15–25 Mev, with a view to studying the nuclear absorption process in oxygen. The known energy response characteristics of several "activity detectors" (Zn64(γ, n)Zn63, C12(γ, n)C11, S32(γ, d)P30, O16(γ, n)O15) to bremsstrahlung were employed in these measurements.The experimental values of the attenuation ratios were compared to the predicted values calculated on the basis of various assumptions concerning the nuclear absorption process.The best description of the nuclear absorption process in oxygen appears to be continuous absorption on which relatively small absorption peaks are superimposed.

Photon-Induced L-Shell X-Ray Production Cross Sections for Lanthanides at 59.54 keV

2017 ◽  
Vol 890 ◽  
pp. 223-226 ◽  
Author(s):  
Rıdvan Durak ◽  
Ferdi Akman ◽  
Abdulhalik Karabulut
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Production Cross ◽  
Theoretical Data ◽  
Experimental Results ◽  
X Rays ◽  
X Ray ◽  
Reflection Geometry ◽  
Experimental Values ◽  
Annular Source

The Ll, Lα and Lβ X-ray production cross sections for Pr, Nd, Sm, Eu, Gd and Tb elements were determined using a reflection geometry. The excitation was performed with a 241Am radioactive annular source and the L X-rays emitted from targets were counted with a high-resolution Si (Li) detector. The experimental values were compared with other available experimental results and theoretical data. An agreement is observed between the measured and other experimental results or theoretical data.

scholarly journals Numerical simulation of the X-ray energetics in spherical plasmas

1988 ◽  
Vol 6 (2) ◽  
pp. 343-351 ◽  
Author(s):  
J. P. Dinguirard ◽  
D. Mostacci ◽  
J. Briand ◽  
A. Gomes ◽  
J. C. Kieffer ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Computer Simulations ◽  
Initial Pressure ◽  
X Rays ◽  
Absorption Process ◽  
X Ray ◽  
Inverse Bremsstrahlung ◽  
Lawson Criterion ◽  
Glass Microballoons ◽  
Inverse Bremsstrahlung Absorption

1-D computer simulations have been performed to study the influence of X-rays preheating on the compression of spherical laser-produced plasmas. The targets are glass microballoons filled with Neon at the initial pressure 10 bars. It is assumed that the only significant absorption process in the Neon is by inverse bremsstrahlung absorption. The results indicate that the radiative preheating energy has a nonnegligible effect on the compression, and a study of the Lawson criterion shows that this effect is more important for high-Z target shell materials and for thicker shells.

scholarly journals A Low Energy Gas Scintillation Proportional Counter for the SAX-X-Ray Astronomy Satellite

1990 ◽  
Vol 123 ◽  
pp. 457-461
Author(s):  
A.N. Parmar ◽  
A. Smith ◽  
M. Bavdaz
Keyword(s):  
Proportional Counter ◽  
Space Science ◽  
Low Energy ◽  
X Rays ◽  
Science Department ◽  
Energy Response ◽  
X Ray ◽  
Thin Plastic

AbstractThe payload of the italian/Dutch satellite SAX will include a set of four concentrators each with a geometric area of 90 cm2. Imaging GSPCs will be located at the focal planes of the concetrators. The Space Science Department of ESA will provide one of these GSPCs which will be sensitive to X-rays with energies between 0.1-10 keV. In order to achieve such a low-energy energy response, a driftless configuration and a thin plastic window have been adopted. At 6 keV the collecting area will be 50 cm2 and the energy and angular resolutions 8% and 1.6′ FWHM, respectively.

scholarly journals Application of X-rays Diffraction for Identifying Thin Oxide Surface Layers on Zinc Coatings

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1005
Author(s):  
George Vourlias
Keyword(s):  
Grazing Incidence ◽  
Oxide Surface ◽  
Zinc Oxide Film ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thin Oxide Films ◽  
Thin Oxide ◽  
Predicted Values ◽  
Zinc Coatings

Structural characterization of compound material coatings is usually achieved using time-consuming and destructive techniques such as optical and electrical microscopy, which require the use of grinding processes not always compatible with the material. This paper reports on the effective use of a theoretical model based on X-ray diffraction to calculate the thickness and composition of thin oxide films formed on the surface of zinc coatings. Zinc coatings are widely used in industrial application as protective layers against the atmospheric corrosion of steel substrates. The thickness of single- and multi-layer coatings is estimated using grazing incidence X-ray diffraction and various incidence angles. The coatings were grown using hot-dip, pack cementation and thermal spray techniques, and their experimental characteristics were compared to the theoretically predicted values of thickness and composition. The results indicate the formation of a thin zinc oxide film on top of each coating, which acts as an isolation layer and protects the surface of the sample against the environmental corrosion. Finally, the penetration depth of the X-rays into the zinc-based coatings for grazing incidence and Bragg–Brentano X-ray diffraction geometries were calculated using theoretical equations and experimentally confirmed.

K shell absorption jump ratios and jump factor measurements for some elements in the range of 40 ≤ Z ≤ 50

2019 ◽  
Vol 97 (7) ◽  
pp. 786-790
Author(s):  
A. Turşucu
Keyword(s):  
Point Source ◽  
Atomic Number ◽  
Semiconductor Detector ◽  
Theoretical Calculations ◽  
Energy Dispersive ◽  
X Rays ◽  
Number Range ◽  
X Ray ◽  
Edxrf Technique ◽  
Experimental Values

In this study, K shell absorption jump ratios (JK) and jump factors (rK) of specimens in the atomic number range of 40 ≤ Z ≤ 50 were measured using the energy dispersive X-ray fluorescence (EDXRF) technique. Related specimens were excited using 59.54 keV γ-photons that were radiated from a 241Am point source. Typical K X-rays emitting from specimens were detected from silicon drifted lithium (Si(Li)) semiconductor detector. Derived JK and rK values of related specimens were compared with calculated theoretical and other experimental values. The agreement of measured values was reasonable with theoretical calculations.

Angular variations of K and L X-ray fluorescence cross sections for some lanthanides

2008 ◽  
Vol 86 (2) ◽  
pp. 361-367 ◽  
Author(s):  
I Han ◽  
M Şahin ◽  
L Demir
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Emission Angle ◽  
X Rays ◽  
X Ray ◽  
Isotropic Distribution ◽  
Fluorescence Cross Section ◽  
Intensity Ratios ◽  
Experimental Values ◽  
Photon Source

Kα, Kβ, Lα, and Lβ X-ray fluorescence cross sections for lanthanides in the atomic range 62 ≤ Z ≤ 68 (Sm, Eu, Gd Tb, Dy, Ho, and Er) were simultaneously measured by 59.54 keV incident photon energy at five angles ranging from 120° to 160°. The measurements were performed using an Am-241 radioisotope as the photon source and a Si(Li) detector. The Lα X-ray fluorescence cross section (σLα) was found to decrease with increasing emission angle and showed an anisotropic distribution of Lα X-rays. Kα, Kβ, and Lβ X-ray fluorescence cross sections (σKα, σKβ, and σLβ) were observed to be angle-independent and showed an isotropic distribution of Kα, Kβ, and Lβ X-rays. The Kα and Kβ X-rays originate from filling of the K shell (J = 1/2) vacancies, Lβ X-rays from filling of the L1 and L2 (J = 1/2) subshell vacancies, and Lα X-rays from filling of the L3 subshell (J = 3/2) vacancy. The fluorescent X-rays originating from the vacancy states with J = 1/2 are isotropic and unpolarized, but fluorescent X-rays originating from the vacancy states with J > 1/2 are anisotropic and polarized. Thus, the atomic inner shells vacancy states with J > 1/2 are aligned whereas vacancy states with J = 1/2 are not aligned. Lα fluorescence X-rays have an anisotropic distribution, while Kα, Kβ, and Lβ fluorescence X-rays have isotropic distribution. Furthermore, the IKβ/IKα, ILα/IKα}, ILβ/IKα, and ILβ/ILα intensity ratios for the elements under investigation were determined. The experimental cross sections and intensity ratios for Kα, Kβ, Lα, and Lβ fluorescence X-rays were also determined, and these experimental values were compared with our calculated theoretical values.PACS Nos.: 32.30.Rj, 32.80.Cy

K X-ray fluorescence parameters of peripherally and non-peripherally tetra-substituted zinc (II) phthalocyanines

2017 ◽  
Vol 95 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Erhan Cengiz ◽  
Muhammet Dogan ◽  
Zekeriya Biyiklioglu ◽  
Dilek Cakir ◽  
Engin Tirasoglu ◽  
...  
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
X Rays ◽  
Pure Zinc ◽  
X Ray ◽  
Fluorescence Parameters ◽  
Zinc Phthalocyanines ◽  
Γ Rays ◽  
Experimental Values ◽  
Shell Production

The K shell production cross-sections and Kβ to Kα X-ray intensity ratios of peripherally and non-peripherally tetra-substituted zinc (II) phthalocyanine complexes were determined using energy dispersive X-ray fluorescence spectrometry (EDXRF). The effect of substituent position on these parameters was also investigated. The complexes were excited by 59.5 keV γ-rays from an 241Am annular radioactive source and K X-rays emitted by the complexes were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The experimental results of the zinc phthalocyanines having the same ligand substituted peripheral and non-peripheral were compared with each other, theoretical, and experimental values of pure zinc.

Measurements of radiative vacancy transfer probabilities from L3 subshell to M and N subshells of Sm and Eu in halogen compounds

2018 ◽  
Vol 96 (2) ◽  
pp. 202-207
Author(s):  
B.G. Durdu
Keyword(s):  
X Rays ◽  
X Ray ◽  
Halogen Compounds ◽  
Radioisotope Source ◽  
Γ Rays ◽  
Intensity Ratios ◽  
Experimental Values

The radiative vacancy transfer probabilities from the L3 subshell to the M and N subshells for Sm and Eu and their compounds have been measured using L shell fluorescence yields and X-ray intensity ratios. The samples were excited by 59.5 keV γ-rays, which were emitted from an Am-241 radioisotope source. The L X-rays emitted from samples were counted by a Si(Li) detector with a resolution of 155 eV at 5.9 keV. The experimental values were compared with the calculated theoretical values for pure Sm and Eu.

scholarly journals X-Ray spectrometric studies using thin silicon crystals. Advantages and applications

2019 ◽  
Vol 11 ◽  
Author(s):  
A. G. Karydas ◽  
Ch. Zarkadas ◽  
A. Kyriakis ◽  
J. Pantazis ◽  
A. Huber ◽  
...  
Keyword(s):  
Proton Irradiation ◽  
Silicon Crystal ◽  
Crystal Thickness ◽  
X Rays ◽  
Energy Response ◽  
X Ray ◽  
Xrf Analysis ◽  
Average Atomic Number ◽  
Silicon Crystals ◽  
Thin Crystal

This paper presents the peak-to-background ratio improvement, which can be achieved in PIXE and XRF applications by the use of thin crystal detectors. This improvement becomes apparent in the presence of an intense γ-ray source, which can be produced either after proton irradiation of a sample (PIXE), or after the deexcitation of the radionuclide in Radioisotope induced XRF analysis (RIXRF). In order to study theoretically the energy response of a silicon crystal in the X-ray energy region with respect to its thickness and the energy of the incident yradiation, a Monte-Carlo simulation was performed. Experimentally, two detectors having crystal thickness of 300 urn and 3 mm respectively were employed in specific analytical applications of PIXE, PIXE induced XRF and RIXRF techniques. The peak-to-background ratios obtained for various characteristic X-rays were compared between the two detectors. The performance of the two detectors was also compared in monochromatic XRF analysis of samples with low average atomic number matrix content.

MEASUREMENT OF GERMANIUM ESCAPE PEAKS IN PIXE SPECTRA RECORDED USING HIGH PURITY Ge (HPGe) DETECTOR

2009 ◽  
Vol 19 (01n02) ◽  
pp. 67-76
Author(s):  
SANJIV KUMAR ◽  
G. L. N. REDDY ◽  
V. S. RAJU
Keyword(s):  
Quantitative Analysis ◽  
High Purity ◽  
Hpge Detector ◽  
X Rays ◽  
Pixe Analysis ◽  
Escape Peak ◽  
X Ray ◽  
High Purity Germanium ◽  
Experimental Values

This paper deals with studies on Ge K α and K β escape peaks in particle induced X-ray emission (PIXE) spectra recorded by a high purity germanium (HPGe) detector. A knowledge of the energies and intensities of these escape peaks is desirable for accurate qualitative as well as quantitative analysis of elements by PIXE. The spectral interferences caused by Ge K escape peaks in the determination of Fe in U by PIXE are highlighted for illustration. A simple theoretical approach based on the production of Ge K X-rays inside the Ge crystal of the detector during the process of detection of the incident characteristic X-rays and the subsequent escape of a fraction of the produced radiations from the crystal, is described to calculate the intensity ratio of the Ge escape peak to its parent characteristic X-rays. The calculated values are in agreement with the experimental values and those estimated using the formulation provided in GUPIX software for PIXE. The Ge K escape peaks are very prominent; the intensities of Ge K α escape peaks, from bromine to silver, range from 15% to 6% of those of their respective K α X-rays. These intensities are, in general, considerably higher compared to those of Si escape peaks in spectra recorded by Si ( Li ) detector. Ge K escape peaks therefore may give rise to severe interferences. The present approach provides a precise (~8%) determination of the intensity of an escape peak and thereby facilitates a reliable PIXE analysis.

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