CHARACTERIZATION OF A FEW GEM STONES BY X-RAY EMISSION TECHNIQUES (EDXRF AND EXTERNAL PIXE)

2010 ◽  
Vol 20 (03n04) ◽  
pp. 127-134
Author(s):  
DAISY JOSEPH
Keyword(s):  
Trace Element ◽  
Periodic Table ◽  
X Rays ◽  
Testing Laboratory ◽  
X Ray ◽  
Ion Accelerator ◽  
Natural Zircon ◽  
Folded Tandem Ion Accelerator ◽  
Kapton Foil

X-ray Emission Techniques (EDXRF) and External Proton Induced X-ray Emission Technique (PIXE) have been used to characterize 13 gem stones obtained from Gem Testing Laboratory, Jaipur, India. Radioisotope sources 109 Cd and 241 Am were used to excite the gem stones to generate K and L X-rays in the low and high Z region of the periodic table to investigate trace element inclusions besides the main matrix. A proton beam of 4 MeV energy and current of 8 nA intensity were extracted from the FOTIA (Folded Tandem Ion Accelerator) at VandeGaaff Accelerator, Trombay, Mumbai in air through a Kapton foil of 8 micrometer thick mounted on a Teflon cone. Gem stones such as Labradorite Feldspar, Moonstone Feldspar, Almandine Garnet, Tsavorite Garnet, Apatite, Natural Spinel, Natural Zircon, Spessartine Garnet, Natural Ruby (Lead filled), Natural Ruby were characterized for their elemental profile to see the differences in composition besides the main matrix differences. Elements such as Ca , Ti , V , Cr , Mn , Fe , Cu , Zn , Sr , Y and Zr were detected.

PIXE STUDIES ON GOLD STANDARDS BY PROTONS OF ENERGY 3.3 MeV

2004 ◽  
Vol 14 (03n04) ◽  
pp. 141-146 ◽  
Author(s):  
DAISY JOSEPH ◽  
A. SAXENA ◽  
S. K. GUPTA ◽  
S. KAILAS
Keyword(s):  
Proton Beam ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
Ion Accelerator ◽  
Folded Tandem Ion Accelerator ◽  
Certified Values ◽  
A Current ◽  
Gold Standards

Proton Induced X-ray Emission Technique (PIXE) has been used in analyzing Gold standards of 22, 20, 18, and 14 karats with a proton beam of Energy 3.3 MeV at the newly commissioned Folded Tandem Ion Accelerator (FOTIA) at B.A.R.C, Trombay. Well resolved Au and Ag X-rays were detected at a current of 3 nA . Percentage values of gold and silver were calculated and were checked with those obtained by Energy Dispersive X-ray Fluorescence (EDXRF) Method and were found to be in agreement with the certified values as well as those obtained by XRF.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

scholarly journals Integration of Dental Implants in Conjunction with EDTA-Conditioned Dentin Grafts: An Experimental Study

2021 ◽  
Vol 9 (6) ◽  
pp. 63
Author(s):  
Payam Farzad ◽  
Ted Lundgren ◽  
Adel Al-Asfour ◽  
Lars Andersson ◽  
Christer Dahlin
Keyword(s):  
Direct Contact ◽  
Mineral Content ◽  
X Rays ◽  
X Ray ◽  
Dentin Surface ◽  
Significant Difference ◽  
C And N ◽  
Micro Implants ◽  
Demineralized Dentin

This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis.

The influence of X-ray coherence length on TXRF and XSW and the characterization of nanoparticles observed under grazing incidence of X-rays

2009 ◽  
Vol 24 (6) ◽  
pp. 792 ◽  
Author(s):  
Alex von Bohlen ◽  
Markus Krämer ◽  
Christian Sternemann ◽  
Michael Paulus
Keyword(s):  
Coherence Length ◽  
Grazing Incidence ◽  
X Rays ◽  
X Ray

X-RAY DIFFRACTION FOR SURFACES AND BURIED INTERFACES

2000 ◽  
Vol 07 (04) ◽  
pp. 437-446 ◽  
Author(s):  
G. RENAUD
Keyword(s):  
Grazing Incidence ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Buried Interfaces ◽  
Surfaces And Interfaces ◽  
Coherent Interfaces

The application of X-rays to the structural characterization of surfaces and interfaces, in situ and in UHV, is discussed on selected examples. Grazing incidence X-ray diffraction is not only a very powerful technique for quantitatively investigating the atomic structure of surfaces and interfaces, but is also very useful for providing information on the interfacial registry for coherent interfaces or on the strain deformation, island and grain sizes for incoherent epilayers.

scholarly journals Closing the gap between electron and X-ray crystallography

2015 ◽  
Vol 71 (6) ◽  
pp. 737-739 ◽  
Author(s):  
Enrico Mugnaioli
Keyword(s):  
Electron Diffraction ◽  
Structure Characterization ◽  
Diffraction Tomography ◽  
X Rays ◽  
Electron Crystallography ◽  
X Ray ◽  
X Ray Crystallography ◽  
Closing The Gap ◽  
Refinement Algorithm

The development of a proper refinement algorithm that takes into account dynamical scattering guarantees, for electron crystallography, results approaching X-rays in terms of precision, accuracy and reliability. The combination of such dynamical refinement and electron diffraction tomography establishes a complete pathway for the structure characterization of single sub-micrometric crystals.

scholarly journals NuSTAR reveals that the heavily obscured nucleus of NGC 2785 was the contaminant of IRAS 09104+4109 in the BeppoSAX/PDS hard X-rays

2018 ◽  
Vol 619 ◽  
pp. A16
Author(s):  
C. Vignali ◽  
P. Severgnini ◽  
E. Piconcelli ◽  
G. Lanzuisi ◽  
R. Gilli ◽  
...  
Keyword(s):  
X Rays ◽  
X Ray ◽  
Star Forming ◽  
Physical Description ◽  
Enhanced Sensitivity ◽  
X Ray Imaging ◽  
First Time ◽  
In Virtue Of

Context. The search for heavily obscured active galactic nuclei has been revitalized in the last five years by NuSTAR, which has provided a good census and spectral characterization of a population of such objects, mostly at low redshift, thanks to its enhanced sensitivity above 10 keV compared to previous X-ray facilities, and its hard X-ray imaging capabilities. Aims. We aim at demonstrating how NGC 2785, a local (z = 0.009) star-forming galaxy, is responsible, in virtue of its heavily obscured active nucleus, for significant contamination in the non-imaging BeppoSAX/PDS data of the relatively nearby (≈17′) quasar IRAS 09104+4109 (z = 0.44), which was originally mis-classified as Compton thick. Methods. We analyzed ≈71 ks NuSTAR data of NGC 2785 using the MYTorus model and provided a physical description of the X-ray properties of the source for the first time. Results. We found that NGC 2785 hosts a heavily obscured (NH ≈ 3 × 1024 cm−2) nucleus. The intrinsic X-ray luminosity of the source, once corrected for the measured obscuration (L2−10keV ≈ 1042 erg s−1), is consistent within a factor of a few with predictions based on the source mid-infrared flux using widely adopted correlations from the literature. Conclusions. Based on NuSTAR data and previous indications from the Neil Gehrels Swift Observatory (BAT instrument), we confirm that NGC 2785, because of its hard X-ray emission and spectral shape, was responsible for at least one third of the 20–100 keV emission observed using the PDS instrument onboard BeppoSAX, originally completely associated with IRAS 09104+4109. Such emission led to the erroneous classification of this source as a Compton-thick quasar, while it is now recognized as Compton thin.

An Association of Mercury with Selenium in Inorganic Mercury Intoxication

1985 ◽  
Vol 4 (6) ◽  
pp. 637-642 ◽  
Author(s):  
T. Aoi ◽  
T. Higuchi ◽  
R. Kidokoro ◽  
R. Fukumura ◽  
A. Yagi ◽  
...  
Keyword(s):  
Trace Element ◽  
Inorganic Mercury ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
Tubular Cells ◽  
Molecular Ratio ◽  
Renal Tubular Cells ◽  
Mercury Intoxication ◽  
Renal Tubular

1 Energy dispersive X-ray analysis was performed on the renal tubular cells of two patients with inorganic mercury intoxication. 2 Some lysosomes of these cells consisted of unusual matrices of aggregated electron-dense grains which were positive for mercury, selenium and sulphur. 3 Though maps of the specific X-rays of both mercury and selenium coincided exactly with these lysosomes, the molecular ratio of selenium to mercury ranged between zero and 2.9. 4 It is unlikely that the trace element of selenium and exogenous inorganic mercury are deposited in the lysosomes independent of each other, but rather their coexistence in the characteristic lysosomes strongly suggests a compound formed by binding mercury to the SeH residues of selenoprotein.

POSITRON FACILITIES TESTS OF THE X-RAYS PRODUCED BY CRYSTALLINE UNDULATORS

2005 ◽  
Vol 19 (03) ◽  
pp. 85-98 ◽  
Author(s):  
S. BELLUCCI
Keyword(s):  
Positron Beam ◽  
Precise Determination ◽  
X Rays ◽  
Experimental Conditions ◽  
X Ray ◽  
Accelerated Particles

One of the main involvements of the INFN-Laboratori Nazionali di Frascati group in channeling researches is described, i.e. the crystal undulator R & D, with the characterization of the crystal undulator prototypes with SEM and the positron beam. We consider a precise determination of the optimal experimental conditions for channeling of this kind of accelerated particles through such microstructured crystals, as promising candidates for producing X-ray beams.

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