Combined XRD and XRF Analysis for Portable and Remote Applications

1994 ◽  
Vol 38 ◽  
pp. 319-324
Author(s):  
Jonathan A. Kerner ◽  
Edward D. Franco ◽  
John Marshall
Keyword(s):  
Powder Diffraction ◽  
Tilt Angle ◽  
Single Photon ◽  
Fluorescence Analysis ◽  
Low Energy ◽  
Energy Limit ◽  
Pure Sample ◽  
X Ray ◽  
Diffraction Peaks ◽  
Prototype Instrument

Abstract A prototype instrument, which provides x-ray powder diffraction and x-ray fluorescence analysis in a compact unit, has been developed to support the needs of NASA for planetary exploration. The instrument uses a 9-watt Fe-anodc x-ray tube and CCD in a fixed geometry for recording powder patterns with a 2θ range of 35°. The fluorescence spectrum for elements below Fe is collected simultaneously with the diffraction data. A shuttered Cd-109 isotopic source with emissions at 22 and 80 keV is used to excite higher energy fluorescence. The low-energy limit for discriminating single photon events was found to be ∼1.5 keV. Al-K could be distinguished from a pure sample, but the spectrum below 6 keV was degraded by the read noise of the CCD, which introduced spectral artifacts. Diffraction peaks from halite had a FWHM of ∼1°(2θ), with major contributions to the width from the use of slit collimation on the source and the low tilt angle of the sample.

scholarly journals Radionuclide x-ray fluorescence analysis of selected elements in agrimony tea samples with preconcentration

2013 ◽  
Vol 60 (2) ◽  
pp. 29-36
Author(s):  
Mikušová V. ◽  
Lukačovičová O. ◽  
Havránek E.
Keyword(s):  
Elemental Analysis ◽  
Analytical Method ◽  
Fluorescence Analysis ◽  
Low Energy ◽  
X Ray ◽  
Nitrocellulose Filter ◽  
Nuclear Analytical Method ◽  
Energy Gamma ◽  
Solid Form

Abstract The contents of selected elements (Mn, Fe, Co, Ni, Cu, Zn, Hg and Pb) in samples of loose tea of agrimony “Repikovy čaj” (Agrimonia eupatoria L.) were studied in this work. Identification and determination of the selected elements content were performed using X-ray fluorescence spectrometry - the nuclear analytical method based on the interaction between low-energy gamma and X radiation and analysed substance. Solid form samples were pressed in tablets and directly analysed. Prepared infusions were analysed after the preconcentration of the elements using precipitation with thioacetamide and ammonium diethyldithiocarbamate with subsequent filtration of created precipitates through a nitrocellulose filter. Detection limits obtained from both methods were compared and their suitability for elemental analysis of plant preparations was discussed.

X-Ray Fluorescence Analysis at Room Temperature with an Energy Dispersive Mercuric Iodide Spectrometer

1979 ◽  
Vol 23 ◽  
pp. 249-256
Author(s):  
M. Singh ◽  
A.J. Dabrowski ◽  
G.C. Huth ◽  
J.S. Iwanczyk ◽  
B.C. Clark ◽  
...  
Keyword(s):  
Room Temperature ◽  
Fluorescence Analysis ◽  
Low Energy ◽  
Cryogenic Cooling ◽  
Energy Dispersive ◽  
Entrance Window ◽  
X Rays ◽  
Mercuric Iodide ◽  
X Ray ◽  
Present Design

We have previously reported on the uniqueness and potential of room-temperature spectrometry of low-energy x-rays with a mercuric iodide (HgI2) detector (1,2,3). In this paper we emphasize the use of HgI2 detectors for x-ray fluorescence (XRF) analysis.Because no vacuum plumbing or cryogenic cooling is required, the design of a mercuric iodide room-temperature x-ray spectrometer is extremely simple. Our present design consists of coupling a detector directly to the first-stage FET in a modified Tennelec 161 D preamplifier and making the configuration “light-tight”. Aside from providing a suitable entrance window, there are no other requirements for routine spectroscopy.

Unusual Matrix Fluorescence Effects in X-Ray Fluorescence Analysis

1979 ◽  
Vol 23 ◽  
pp. 111-115
Author(s):  
J. W. Criss
Keyword(s):  
Fluorescence Analysis ◽  
Pure Element ◽  
Pure Sample ◽  
X Ray ◽  
Fundamental Parameters

AbstractOn the basis of fundamental-parameters calculations of x-ray fluorescence intensities, it is predicted that relative intensities much greater than one can be observed from thick, homogeneous samples. That is , the intensity of a particular line from a mixture of two or more elements can be much greater than the intensity from the pure element. Similarly, the intensity from a mixture of compounds can be greater than the intensity from a pure sample of the compound containing the emitting element.

Rietveld Structure Refinement of Metastable Lithium Disilicate Using Synchrotron X-Ray Powder Diffraction Data From the Daresbury SRS 8.3 Diffractometer

1990 ◽  
Vol 5 (3) ◽  
pp. 137-143 ◽  
Author(s):  
R.I. Smith ◽  
A.R. West ◽  
I. Abrahams ◽  
P.G. Bruce
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Powder Diffraction Data ◽  
X Ray ◽  
New Instrument ◽  
Diffraction Peaks

AbstractThe crystal structure of metastable Li2Si2O5, Fw = 150.05, has been refined by the Rietveld method using high resolution X-ray powder diffraction data recorded at the Daresbury Synchrotron Radiation Source on the new 8.3 diffractometer. Li2Si2O5, in keeping with many compounds of interest to the materials scientist, exhibits relatively broad diffraction peaks. It is important to establish the quality of crystal structure data that may be obtained from such materials on this new instrument. Various functions were used to model the peak shape from this instrument; a split-Pearson VII function appeared to be marginally superior to Pearson VII or Pseudo-Voigt functions. Refinement was carried out using the split-Pearson VII in the space group Pbcn (60) and terminated with a = 5.6871(6), b = 4.7846(5), c = 14.645(1) Å, V = 398.50 Å3, Z=4, Dc= 2.502 gcm−3, Rwp = 17.06, Rex = 14.48 and Χ2 = 1.39. The refined parameters are compared with those obtained from a previous single crystal X-ray determination.

scholarly journals Development of low-energy X-ray detectors using LGAD sensors

2019 ◽  
Vol 26 (4) ◽  
pp. 1226-1237 ◽  
Author(s):  
Marie Andrä ◽  
Jiaguo Zhang ◽  
Anna Bergamaschi ◽  
Rebecca Barten ◽  
Camelia Borca ◽  
...  
Keyword(s):  
Energy Range ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Low Energy ◽  
X Rays ◽  
Single Photon Counting ◽  
X Ray ◽  
Internal Gain ◽  
Silicon Sensors

Recent advances in segmented low-gain avalanche detectors (LGADs) make them promising for the position-sensitive detection of low-energy X-ray photons thanks to their internal gain. LGAD microstrip sensors fabricated by Fondazione Bruno Kessler have been investigated using X-rays with both charge-integrating and single-photon-counting readout chips developed at the Paul Scherrer Institut. In this work it is shown that the charge multiplication occurring in the sensor allows the detection of X-rays with improved signal-to-noise ratio in comparison with standard silicon sensors. The application in the tender X-ray energy range is demonstrated by the detection of the sulfur K α and K β lines (2.3 and 2.46 keV) in an energy-dispersive fluorescence spectrometer at the Swiss Light Source. Although further improvements in the segmentation and in the quantum efficiency at low energy are still necessary, this work paves the way for the development of single-photon-counting detectors in the soft X-ray energy range.

scholarly journals Development of a Calibration Method for Quantitative X-ray Powder Diffraction of Size-Segregated Aerosols

1990 ◽  
Vol 34 ◽  
pp. 395-407
Author(s):  
Robert D. Giauque ◽  
Joseph M. Jaklevic ◽  
Linda E. Sindelar
Keyword(s):  
Powder Diffraction ◽  
Chemical Characterization ◽  
Incident Beam ◽  
Fluorescence Analysis ◽  
Calibration Method ◽  
X Rays ◽  
Beam Particle ◽  
X Ray ◽  
Matrix Enhancement ◽  
Secondary Extinction

X-ray powder diffraction (XPD) is an important tool for the chemical characterization of atmospheric aerosol samples particularly when combined with elemental analysis obtained from X-ray fluorescence (XRF) measurements of the same specimen. Aerosol samples obtained in typical monitoring studies consist of thin, uniform deposits of particles corresponding to a known size distribution with aerodynamic equivalent diameters of less than 10 microns.This is an ideal form for X-ray fluorescence analysis since absorption and matrix enhancement effects are minimized. However, the ability to perform quantitative X-ray powder diffraction without the use of internal standards is restricted by several factors which affect the linearity of response between diffracted intensity and sample concentration. In addition to the normal photoelectric absorption due to passage of the X-rays through the sample, XPD intensities can be affected by primary and secondary extinction due to diffraction of the incident beam, particle size effects and preferred orientation of particles.

The Use of Fourier Self-Deconvolution to Resolve Overlapping X-Ray Powder Diffraction Peaks

1989 ◽  
Vol 4 (3) ◽  
pp. 144-151
Author(s):  
Ernest E. Armstrong ◽  
David G. Cameron
Keyword(s):  
Powder Diffraction ◽  
Curve Fitting ◽  
Weight Percent ◽  
Quantitative Information ◽  
X Ray ◽  
Comparison Of Results ◽  
Overlapping Peaks ◽  
Diffraction Peaks

AbstractFourier self-deconvolution has been successfully applied as a means of obtaining semi-quantitative information by resolving the overlapping peaks in X-ray powder diffractograms collected from mixtures of kaolinite and ripidolite. A series of diffractograms were collected from known mixtures of the two minerals. The diffractograms were then processed using Fourier self-deconvolution over a selected range between 23 and 27° 2θ (encompassing the overlapping peaks of kaolinite (002) and ripidolite (004) at 24.85 and 25.13° 2θ, respectively). Once deconvoluted, areas under individual peaks of kaolinite and ripidolite were calculated using curve fitting. The calculated percentage of kaolinite in the mixtures was then plotted versus the true weight percent of kaolinite. The same procedure was conducted on the original diffractograms using only curve fitting without first deconvoluting. A comparison of results shows that, provided the number of peaks are known, both methods give nearly equal results. However, Fourier self-deconvolution, by increasing the resolution, greatly improves the ability to detect overlapping peaks.

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