bluuebunny/crossref_metadata_2025_split huggingface dataset:
X-Ray Fluorescence Analysis at Room Temperature with an Energy Dispersive Mercuric Iodide Spectrometer
Authors: Singh M. , Dabrowski A.J. , Huth G.C. , Iwanczyk J.S. , Clark B.C. , Baird A.K. 
Published: March 2019

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.
Advances in the Computer Indexing of Powder Patterns
Authors: Smith Gordon S. 
Published: March 2019

AbstractIndexing of powder-diffraction patterns by computer techniques has advanced to the state that it is now often possible to determine unit-cell dimensions and crystal system for an unknown material solely from its powder-diffraction data. This indexing is fully automated, proceeding directly from positions of observed diffraction lines as input, with decision-making steps being made by a computer. Ease of indexing depends on quality of data (accuracy and completeness), volume of the unit cell, and symmetry of the crystal system. In general, a powder pattern of a triclinic compound with a large unit cell requires a more accurate and complete data-set for successful indexing than does a cubic material having a small unit cell. Fortunately, data from a well-aligned diffractometer or Guinier camera ordinarily suffices for computer indexing. Because of systematic errors in the low-lying diffraction lines, data from the Debye-Scherrer technique usually are not adequate for computer indexing (except for the simpler cases). A brief review of the strategies/algorithms of some of the computer indexing codes now available is given. Criteria for assessing the reliability of a particular computer- assisted indexing are discussed. Finally, attention is directed toward future developments such as by automating the collection of powder- diffraction data, analyzing data by computer data processing, and increasing the speed and reliability of computer indexing.
A Position-Sensitive Proportinal Counter for Residual Stress Measurement by means of Microbeam X-Rays
Authors: Yoshioka Yasuo , Hasegawa Kert-ichi , Mochiki Koh-ichi 
Published: March 2019

AbstractA position-sensitive proportional counter (PSPC) with high counting efficiency has been made for stress analysis with low intensity X-rays such as microbeam X-rays.This PSPC system has made it possible to measure the residual stress in a small region such as a fatigue crack tip in very short time compared with the measurement by standard diffractometer or film methods.
Instrumentation for X-Ray Diagnostics of Plasmas*
Authors: Violet C. E. 
Published: March 2019

AbstractMeasurements of x-rays emitted by hot plasmas provide a powerful diagnostic method of determining important plasma parameters and suggest certain types of plasmas as possibly useful x-ray sources. Instrumentation to accomplish these measurements for various types of plasmas are reviewed. State-of-the-art x-ray spectrometers, calorimeters, and source-imaging devices, designed especially for plasmas generated by focused, nanosecond laser pulses are described. Possibilities of time-resolved measurements on such short-lived plasmas are discussed.
Amplification of Soft X-Rays in a Picosecond Laser-Produced Plasma
Authors: Lacour B. , Maillet M. , Michon M. , Tuilier M. H. 
Published: March 2019

AbstractWe investigate the possibilities of amplification of soft x rays in a low Z plasma produced by a picosecond laser. Inversion of population could take place between metastable and fundamental state of lithium-like ions.
X-Ray Pulse Calorimetry of Laser-Produced Plasmas*
Authors: Violet C. E. , Petruzzi J. , McQuaid J. H. , Boster T. A. , Richards L. M. , Mead S. W. , Saroyan R. A. , Swain J. E. 
Published: March 2019

AbstractThe x-ray energy emitted from laser-produced plasmas has been measured under various experimental conditions. Two Nd-glass lasers were used in separate experiments to focus pulsed laser light on planar targets. X-ray fluences were measured with newly developed silicon detector calorimeters. Results for various experimental conditions are reported in terms of the efficiency with which the laser light was converted to x-ray energy by plasma production.
X-Ray Fluorescence Analysis with Transmission Target Tubes
Authors: Zulliger H. R. , Stewart J. E. 
Published: March 2019

AbstractTodays demand for rapid trace element analysis in pollution control and resource materials has led to the development of a completely automatic, very sensitive and stable Si(Li) X-ray analyzer. The key element, a transmission target tube, which has inherently a very clean monochromatic X-ray output, has been studied in view of efficiency, sensitivity and stability. The transmission target tube requires different operating criteria than conventional X-ray tubes. An analysis was made to “explain” these differences using fundamental X-ray physics. Studies included various experiments directly applied to practical problems in analysis of pollutants and mineral resource materials.
Application of Proton Induced X-Ray Emission Analysis to the St. Louis Regional Air Pollution Study
Authors: Akselsson R. , Orsini C. , Meinert D. L. , Johansson T. B. , Van Grieken R. E. , Kaufmann H. C. , Chapman K. R. , Nelson J. W. , Winchester J. W. 
Published: March 2019

AbstractThe St. Louis aerosol was sampled during the period 16-22 August 1973 simultaneously at two locations using cascade impactors for sequential 12-hour samples. The six particle size fractions of each sampling were individually analyzed using PIXE for elements from S to Br and beyond and for heavy elements including Pb which permitted time variations of concentrations and particle size distributions to be followed and related to meteorological changes during the sampling period. In addition, the data were compared with average levels of the elements in coastal north Florida and maritime Bermuda as well as at a third St. Louis site. From this it appeared that some of the concentrations in St. Louis were at natural levels whereas others appeared to be higher and linked to air pollution sources. These relationships and others in this study may lead to criteria for distinguishing between pollutants and natural background in urban aerosols.
A Versatile X-Ray Stress Analyzer Using a Position Sensitive Detector
Authors: Yoshioka Yasuo , Hasegawa Ken-ichi , Mochiki Koh-ichi 
Published: March 2019

Instrumentation for X-ray stress analysis has been advanced rapidly in the last few years. Especially, the time required for data accumulation has been remarkably reduced without motion of the detector by using a new X-ray detector called a position sensitive detector (PSD). Applications of PSD to the field of X-ray stress analysis were carried out by James and Cohen, Ruud and Barrett, and the authors. In our laboratory, several position sensitive proportional counters (PSPCs) were designed and manufactured for residual stress measurements. Results show that the PSPC method is a powerful alternative to the conventional counter method or the film method.This paper reports a design of a versatile PSPC X-ray stress analyzer for use in industry and the laboratory.
X-Ray Diffraction Evaluation of Adhesive Bonds and Stress Measurement With Diffracting Paint
Authors: Barrett Charles S. , Predecki Paul 
Published: March 2019

AbstractX-ray diffraction is found effective in disclosing the distribution of stresses over the surface of adhesively bonded lap joints when loads well below the yield point are applied. When a pair of 6061-T6 aluminum strips 1/16” or 1/32” thick and 3/4” wide is adhesively bonded in a single lap joint and loaded in tension, maps giving the distribution of the X-ray-measured stresses show the limits of the bonded area with an accuracy about equal to the width (1 mm) cf the irradiated area along the specimen. Attendant bending stresses resulting from the loading are also registered. Stress values can be obtained from the observed diffraction angles by calibration with tensile tests of a single unbonded strip. Similar results are obtained for graphite/epoxy laminates adhesively bonded in a single lap joint to aluminum when diffraction is from the aluminum, but a lower accuracy is obtained when diffraction is from the filled composite.Another X-ray method was developed for measuring applied (not pre-existing residual) stresses, and for mapping their distribution around a joint. A thin layer of epoxy paint containing a diffracting filler (say aluminum or silver powder) is applied to a specimen and cured. Diffraction from this paint yields shifts in diffraction angle approximately proportional to the magnitude of applied stresses. The limits of the bonded area in single lap joints under load are disclosed. Both methods appear, therefore, to be practicable for mapping the areas that are properly bonded, and presumably also for non-destructive evaluation of bond defects.
The Characterization of Alpha and Intermediate Aluminum Oxide Mixtures by Semi-Automated XRD
Authors: Burleson John R. 
Published: March 2019

AbstractIntermediate aluminum oxides (aluminas) have broad X-ray diffraction (XRD) peaks. Many of the phases have similar XRD patterns with overlapping of major peaks. To characterize a multi-component alumina mixture several regions of multiple overlapping peaks are examined. Each region is integrated to a single sum without regard for individual peaks. The integrated regions are applied to various ratio functions obtained from single component standards. By using an iterative technique, the functions converge to yield weight fractions for up to six alumina phases.
Use of Compton Scattering in X-Ray Fluorescence for Determination of Ash in Indian Coal
Authors: Pandey H. D. , Haque R. , Ramaswamy V. 
Published: March 2019

AbstractX-ray fluorescence method using Compton scattering for the determination of ash in coal has been systematically studied for application to Indian Coal. Fluorescent intensities from major constituents such as Al2O3, SiO2, TiO2, Fe2O3, CaO and their various combinations were used in conjunction with the reciprocal of the Cr Kα Compton intensity in a regression equation. Varying degrees of correlations were obtained between the values of ash determined by conventional methods and those calculated from X-ray data. It is found that Ti fluorescent intensity plays a major role in the regression equation and its contribution cannot be ignored if the Cr X-ray tube is used.
Improving the Detection Limit in Wavelength Dispersive XRF
Authors: Sipilä Heikki 
Published: March 2019

AbstractThe origin of the background under the signal in the wavelength dispersive XRF has been investigated. The methods of minimizing the background are presented. The bremsstrahlung is eliminated by using a primary filter in front of the X-ray tube. The background generated by the X-ray detector is decreased with a pulse risetime and a pulse interval analyzer. For example, in the fixed uranium spectrometer channel a 500-fold improvement of the peak-to-background ratio was achieved.
Quantitative Analysis of Selected Minor and Trace Elements Through Use of a Computerized Automatic X-Ray Spectrograph
Authors: Fabbi B. P. , Elsheimer H. N. , Espos L. F. 
Published: March 2019

Upgrading a manual X-ray spectrograph, interfacing with an 8K computer, and employment of interelement correction programs have resulted in a several-fold increase in productivity for routine quantitative analysis and an accompanying decrease in operator bias both in measurement procedures and in calculations. Factors such as dead time and self-absorption also are now computer corrected, resulting in improved accuracy. All conditions of analysis except for the X-ray tube voltage are controlled by the computer, which enhances precision of analysis. Elemental intensities are corrected for matrix effects, and from these the percent concentrations are calculated and printed via teletype.Interelement correction programs utilizing multiple linear regression are employed for the determination of the following minor and trace elements; K, S, Rb, Sr, Y, and Zr in silicate rocks, and Ba, As, Sb, and Zn in both silicate and carbonate rock samples. The last named elements use the same regression curves for both rock types. All these elements are determined in concentrations generally ranging from 0.0025% to 4.00%, The sensitivities obtainable range from 0.0001% for barium to 0.001% for antimony. The accuracy, as measured by the
percent relative error for a variety of silicate and carbonate rocks,
is on the order of 1-7%. The exception is yttrium (13.8%).
Photon Standards for Energy and Efficiency Calibration of X-Ray Fluorescence Analyzers
Authors: Notea A. , Segal Y. 
Published: March 2019

AbstractA set composed of barium-133 (7.8y), europium-152g (13.4y), bismuth-207 (30y) and americium-241 (458y), is recommended for energy and efficiency calibration of x-ray spectrometers. It is shown that the set offers over 30 energy lines in the range below 100 keV. The absolute efficiency calibration of Ge(Li) and Si(Li) detectors is demonstrated. The calibrated Ge(Li) was used for the measurement of fluorescence excitation yield from lead excited by various γ sources.
Quantitative Determimatioh of Sulfur, Chlorine, Potassium, Calcium, Scandium and Titanium in Aqueous Solutions by Radioisotopic Excited Fluorescent Spectrometer and by Conventional X-Ray Spectrometer
Authors: Chan Frank L. , Jones W. Barclay 
Published: March 2019

AbstractAn x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.
Application of a Computer-Coupled Radioisotope X-Ray Spectrometer to Analysis of Steels
Authors: Rhodes J. R. , Hunter C. B. , Kellogg D. L. , Sieberg R. D. , Furuta T. 
Published: March 2019

AbstractA compact X-ray energy spectrometer has been developed consisting essentially of a radioisotope X-ray source, a lithium-drifted silicon (or germanium) detector and a small computer. Interchangeable sources enable efficient excitation of K X-rays from Na to U and L X-rays from about Ag to U. Energy resolution of K X-rays from adjacent elements down to Na is possible. Depending on the source and the part of the spectrum examined, the characteristic X-rays from up to about 15 elements can be simultaneously excited and measured, for either qualitative or quantitative multi-element analysis. The computer stores detected spectra and performs simple data processing such as peak recognition, background subtraction, peak integration, ratioing and solution of linear equations.The analysis reported in this paper is the determination of V, Cr, Fe, Co, W and Mo in tool steels and is intended to illustrate the capabilities of the radioisotope X-ray fluorescence analysis technique, and the instrument, for multi-element analysis of a system having fairly complex interelement effects.A 100 mCi Pu-238 source was used to excite the K X-rays of V, Cr, Fe, Co and Mb and the L X-rays of W. The count time used was five minutes per sample. Data reduction consisted essentially of peak integration, background subtraction and solution of sixth order linear matrices of a modified Criss-Birks type. The 36 matrix coefficients were determined using six standards, and were then used to analyze seven other analyzed specimens which were treated as unknowns. The measured values of concentration were in very good agreement with the quoted values. An iteration technique was employed to reduce errors in the matrix inversioiis.
Study of Structural Detail by X-rays of Wavelength Greater than 4Å
Authors: Herglotz H. K. 
Published: March 2019

AbstractSome branches of structural research could benefit from supplemental information provided by “soft” x-rays. Little use is made of these wavelengths because they are difficult to generate at high intensity, hard to collimate, need vacuum for propagation, and are heavily absorbed in the sample. None of these difficulties is insurmountable, however, and it will be shown that the information to be gained is often worth the extra effort.A few theoretical and experimental examples with silver L-radiation (λ ≈ 4.15Å) and aluminum K-radiation (λ ≈ 8.34Å) demonstrate that valuable semiquantitative information on the size and number of aperiodic scatterers in solid samples can be extracted. Other examples show the superior sensitivity of these longer wavelengths to dimensional changes in periodic lattices. Applicability of long-wavelength diffraction is restricted to values of interplanar distance d > λ/2. Valuable information about lattice imperfection can be gained from broadening of the reflection at larger glancing angles. It is shown that the heavy absorption of these wavelengths in the sample is not necessarily prohibitive.The instrumentation used in these studies was designed for routine operation by laboratory personnel without special training. It consists of a demountable high-intensity x-ray source and a multipurpose highvacuum camera. Operation of the x-ray unit resembles that of commercial x-ray diffraction instruments. Because of its greater-flexibility, photographic recording has been practiced so far but could be replaced by electronic readout.
X-ray Astronomy Laboratory at the University of Chicago
Authors: Blake R. L. , Passin T. 
Published: March 2019

AbstractA laboratory has been established with two primary objectives. First it is to permit test and calibration of rocket and satellite x-ray astronomy experiments. Second it is for studies in ultrasoft x-ray physics. The basic units described are a precision x-ray spectrometer, a separate precision spectrograph, direct and fluorescence excitation sources, the rocket payload test chamber, and auxiliary components. Planned applications include measurements of crystal reflection coefficients, rocking curves, light element absorption edge structure, and spectroscopy of solid and high temperature gas sources.
The Application of X-ray Line Broadening to a Study of Substructure Strengthening in Dispersion Strengthened Alloys
Authors: Clegg M. A. , Lund J. A. 
Published: March 2019

AbstractA refined x-ray line profile analysis was used to determine the lattice strain distribution and crystallite domain size in nickel and a series of alloys, Ni-Cr, Ni-ThO2 and Ni-Cr-ThO2 in a wide range of thermo-mechanical conditions. Corrections were made for instrumental broadening and doublet broadening according to Stokes and Rachinger respectively, for errors due to the “hook effect”, for terminal errors in the series arising from Instability of the components, and for the presence of stacking faults and twins on the basis of peak shift and asymmetry. The internal consistency of the x-ray data was reviewed critically and good agreement was found. The values of lattice strain and domain size were used to evaluate the presence of a dislocation substructure and the degree of polygonization of the subgraln boundaries.It was concluded that the thoria-free materials developed much higher lattice strains during cold rolling than did the Ni-ThO2, due it is thought to the operation of multiple slip in the latter. The Ni-Cr-ThO2 also developed high lattice strains during cold rolling, similar to those of the thoria-free lattices, and this was explained by the influence of chromium on cross-slip. It was postulated that the regions of high lattice strain act as driving forces in the process of recrystallization and promote grain growth during heat treatment following cold rolling.The x-ray results were correlated with transmission electron microscopy and tensile data in a parallel study in which models for room temperature and high temperature strengthening were proposed.
Size-Strain and Quantitative Phase Analysis by the Rietveld Method
Authors: Scardi Paolo , Lutterotti Luca , Di Maggio Rosa 
Published: March 2019

AbstractA modified version of the Rietveld method has been developed for quantitative phase analysis in conjunction with crystallite size and microstrain determination.Besides the information on the microstructural disorder in the different phases present in the sample, accurate phase analysis can be performed, even in presence of anisotropic crystallites, taking into account the non-instrumental peak broadening effect in a better way compared to conventional methods.The method has been tested on binary mixtures of corundum, ceria stabilized zirconia and on a polyphase stabilized zirconia sample.
High Resolution X-Ray Powder Diffraction by the Combination of Synchrotron Radiation and Imaging Plate to Observe Electron Distribution by the Maximum Entropy Method
Authors: Takata Masaki , Yamada Manabu , Kubota Yoshiki , Sakata Makoto 
Published: March 2019

AbstractA Debye-Scherrer camera (radius 572 mm) was designed for the use at the Photon Factory BL-6A2. It uses 4 pieces of the Imaging Plate to cover 0° ∼ 160° in 2θ. The profiles measured by the camera had 0.083° full width at half maximum (FWHM) and were rather symmetric compared with conventional X-ray source. The observed profiles were well represented by either the split Pearson VII or pseudo-Voigt function. In order to examine the performance of the new camera, the whole powder data of LiF was analyzed by the Maximum Entropy Method(MEM). The MEM analysis of LiF was successfully accomplished using 20 measured structure factors and gave R(Bragg) 0.25%. The density distribution obtained represented a characteristic feature of ionic crystals and was consistent with the theoretical result of the self-consistent LCAO method.
Characterization of Single- and Multiple-Layer Films by X-Ray Reflectometry
Authors: Huang T. C. , Parrish W. 
Published: March 2019

AbstractPrecision X-ray reflectivity data were obtained with a high-resolution reflectometer equipped with a rotating anode X-ray source and Ge 220 channel monochromators (one placed before and the other after the specimen). The surfaces and buried interfaces of thin films were characterized by ieast-squares refinement of experimental data. Values of thickness, density, and/or roughness of Pt “single-layer” and Pt/Co based multiple-layer films were determined.