bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Observations on the Use of Certain Analyzing Crystals for the Determination of Silicon and Aluminum*
Authors: Chan Frank L.
Published: March 2019

During the past several years, a number of analyzing crystals have been prepared in the U.S. Air Force Aerospace Research Laboratories. Crystals such as alkaline acid malonates, sucrose, pentaerythritol (PET), and several others have been grown with the sole purpose of application in X-ray fluorescence analysis of silicon, aluminum, and other elements of low atomic number. Crystals from natural sources, such as quartz, mica, and gypsum, have also been procured from different parts of the world for this purpose.

Among the analyzing crystals so prepared, pentaerythritol gave the highest count rate for silicon and aluminum. However, since this crystal is organic in nature, great care must be exercised in handling this type of crystal in order to obtain constant count rates. For the analysis of silicon and aluminum, a-quartz crystal gave a somewhat low count rate, but this crystal has certain advantages over the organic crystals, and can be used for analysis of materials having high silicon and aluminum content.

For instance, when using a conventional X-ray emission vacuum spectrograph of standard make, with the latest alterations, one of the PET crystals attained a count rate of 101,870 cps for pure silicon when the instrument was operated at 60 kVP and SO m A with a negligible background count. With a constant potential attachment and operated at 60 kVP and 34 mA, 1.15,600 cps with negligible background count was obtained for silicon. The count rate for aluminum was of the same order of magnitude with somewhat higher background count.

Several sets of standards have been procured and small amounts of silicon and aluminum in these standards have been analyzed by the latest modified vacuum spectrograph. These results are under study and the limit of detection calculated. Procedures and results are described and discussed.
X-Ray Spectrographic Analysis of Automotive Combustion Deposits Without the Use of Calibration Curves
Authors: Wagner J. C. , Bryan F. R.
Published: March 2019

Art X-ray spectrographic technique requiring no calibration curves is used to determine chlorine, bromine, and lead in automotive combustion deposits. Other elements, such as zinc and barium, can probably be determined by the same X-ray technique. The inert dilution method, described by Sherman in 1957, is employed. Improvements in sample preparation have been made to make the procedure more reliable. Results are calculated by the use of a formula, which is shown to be valid even though sample and standard have composition differences which cause interelement-effect errors if calibration-curve techniques are used. Adequate agreement is obtained between the inert dilution X-ray method and chemical procedures.
Composition and Lattice Constant Evaluation of the Garnet System (Dy, Gd)3Ga5O12
Authors: Moudy L. A. , Austerman S. B.
Published: March 2019

Compositional and lattice constant control of non-magnetic garnet substrates are required for suitable lattice matching with epitaxially deposited magnetic thin film. Suitable substrates for this purpose are the simple and mixed rare earth garnets. Lattice constants were obtained on Czochralski grown crystals by conventional x-ray diffraction powder techniques with a precision of ± .0005Å. An x-ray fluorescence method was developed to determine crystal composition with a precision of ± 0.5 percent. The precision with which a can be determined indirectly by x-ray fluorescence is ± 0.0082Å, which is comparable with that from direct measurement.
New Improvements in Routine Quantitative Phase Analysis by X-Ray Diffractometry
Authors: Sahores J.J.
Published: March 2019

The principle of the method that we proposed two years ago (1) to correct the matrix effects in quantitative diffractometry is briefly recalled and recent improvements are described. Some examples taken in geological field illustrate its possibilities.

A new field of application has been explored : thanks to a combination of this method with background measurement, a semi-quantitative estimation of the amount of amorphous material is made possible in any sample.

This correction technique can be used with any regular diffractometer : for this purpose we simply need to add a second measuring channel, the characteristics of which are given.

Finally we describe briefly the complementary electronics which have been designed in order to fully automate the apparatus, from the insertion of the samples to the printing of the results.
The Processing of Energy Dispersion X-Ray Data in a Timesharing Computer
Authors: Marr Harold E. , Campbell William J.
Published: March 2019

A time-sharing computer was used in conjunction with a semiconductor detector and radioisotopic sources to evaluate energy dispersion x-ray analysis for the rapid analysis of copper base alloys. The time-sharing computer served two purposes: to aid in the development of the analytical method and to simulate the action of a dedicated computer that would eventually be used as part of an on-line analytical device. Some of the general capabilities of time-sharing computers are discussed in this paper with some emphasis on the differences between the computer requirements of energy dispersive x-ray methods and conventional x-ray spectrography.

An annular source of americium 24l was used with a secondary fluorescer to excite 23 brass and bronze alloys. The 400 channel spectrum from a multichannel analyzer was recorded on paper tape. A telephone coupled teletype was used to transmit the X-ray spectrum to the central processing facility. Curve fitting and statistical analysis programs similar to those available from most commercial time-sharing computer operations were utilised as well as other programs written at this laboratory for processing digitized spectra.
Evaluation of the Energy Dispersive Detector as a Detector-Filter System for the X-Ray Diffractometer
Authors: Carpenter Davis , Thatcher John
Published: March 2019

A comparison of the relative merits of the energy dispersive derector-pulse height analyzer, scintillation detector-graphite monochromator, and proportional detector-pulse height analyzer combinations.

Typical energy dispersive detectors are not configured for maximum efficiency on the diffractometer. Being only on the order of 3 mm diameter, a good deal of the available information is not collected by the detector. This is especially true with the Wide optics found in modern diffractometers. The energy dispersive detector incorporated into this system is optimized for the x-ray diffractometer. Its detection area is a 1.25 X 0.25 inch rectangle. The resolution is only sufficient to remove the Kβ portion of the spectrum.

Conventional diffractometer techniques incorporate either a scintillation detector-crystal monochromator, or a proportional detector-pulse height analyser combination. The question posed is “what are the advantages in signal to noise ratio and pulse height distribution of the energy dispersive-pulse height analyzer over the more conventional arrangements.”
Intensity Correction Factors for X-Ray Diffraction Measurements of Residual Stress
Authors: Short M. A. , Kelly Carol J.
Published: March 2019

The angular dependent factors which affect the intensities of X-ray diffraction line profiles, as observed on a Standard X-ray diffractometer, are well established. They are the Lorentz factor, the polarization factor, the atomic scattering factor, and the temperature factor. For residual stress analysis, in which measurements are made at non-zero omega (psi) angles, an absorption factor must be added to this list. It is usual, however, in residual stress analysis, to omit two of these factors: the atomic scattering factor and the temperature factor. The omission of these two factors appreciably alters the change in the combined correction factor with change of diffraction angle. The proper angular dependent corrections are in the opposite sense to those customarily employed. The effect of the additional factors on measurements of residual stress are discussed.
X-Ray Diffraction Contrast from Impurity Precipitates in CdS Single Crystals
Authors: Chikawa Jun-ichi
Published: March 2019

Impurity-doped crystals CdS(GaGl3) have been studied by X-ray topography. Some large precipitates are formed close to the crystal surfaces by annealing at 300°C. In the symmetrical Laue case, the precipitates show circular images (30-60 μ in diameter) due to the radial strains around the precipitates which consist of two semicircles separated by a contrast-free plane parallel to the reflecting plane. The observations indicate that the strain field between the crystal surface and precipitate is not responsible for the contrast, and that the images are formed by X-rays which are deviated from the Bragg condition for the perfect region and satisfy the Bragg condition in the strain field on the inside of the precipitate. One of the semicircles is formed by the incident X-rays with larger glancing angles than the Bragg angle and the other with smaller ones. It is concluded that this contrast is due to the strain around a convex lens shaped precipitate.
Lang X-Ray Topographic Studies of Ruby Grown by Different Methods
Authors: Belt Roger F.
Published: March 2019

Crystals of ruby (Al2O3:Cr) are being grown at the present time by several standard procedures, e.g., Verneuil, Czochralski, flux, and hydrothermal. Previous work has indicated wide variations in quality and type of defects. The present study is primarily concerned with ruby grown from PbO-PbF2 fluxes. All crystals were examined in transmission with Mo Kα1 radiation and a Rigaku Denki Lang camera. Samples were either sectioned from larger crystals or obtained as plates with natural growth faces. Results on flux-grown ruby have shown a severely banded substructure due to strain introduced by either the flux or chromium segregation. Crystals with a visible chromium gradient have shown fewer bands in those regions which were depleted of chromium. Annealing studies have been performed on ruby and all banded structure was dispersed into areas of fine particles with a much higher dislocation content. Other features of the substructure are described. These include the observation of Pendellosung fringes in wedgeshaped sections. Areas of nearly 0.5 cm2 were found to be dislocation free. The X-ray results confirm etching experiments but the former yield more information on internal details other than dislocations.

Recent data on sapphire (α-Al2O3) have confirmed several tentative conclusions. Flux grown crystals have some bands due to flux segregation. However, sapphire crystals show higher perfection when compared to ruby. These results have been confirmed by rocking curves obtained on a double crystal X-ray spectrometer used in the parallel position. Measurements on the (00.12) reflection from the natural growth faces were performed with Cu Kα1 radiation. Widths at half the maximum intensity were always found to be larger for ruby than for sapphire. Comparisons were made with respect to a perfect silicon crystal in the same geometry. Some preliminary experiments have been performed on Czochralski ruby prepared by the Linde Company and on hydrothermally grown ruby prepared at Airtron, Examples of defects observed in each case are given. They are highly unique to the growth method. The Lang method is shown to reveal more detail than other X-ray data. A brief discussion of ruby quality as a function of growth method is presented.
The Expansion upon Cooling of Thick Cu2O Films Grown on Copper Substrates
Authors: Swank T. F. , Lawless K. R.
Published: March 2019

During the course of catalytic experiments on bulk copper single crystals, several crystals were intentionally oxidized to form thick (6000 Å) Cu2O films on the copper substrates. These oxidized crystals were investigated by means of a high temperature chamber installed on a General Electric XRD-5 X-ray diffractometer. It was discovered subsequently that the lattice spacings of the Cu2O decreased upon heating and increased upon cooling. Bulk single crystals and polycrystals of copper were oxidized at 3 Torr of air for several hours. All of the oxidized crystals were examined with copper and chromium radiation and both showed similar results. Typical of the results was an oxidized (110) copper disc which showed a net contraction upon heating of 1% for the (110) Cu2O planes. This slightly oriented Cu2O film was distinguished because -it contracted on heating to 440°C from room temperature, then expanded from 440°-540°C, and then expanded again when cooled from 540°C to room temperature. CuO also was detected in the diffraction pattern and the CuO and copper spacings were behaving normally with the temperature changes. A polycrystal of Cu2O was'examined and that, of course, also acted normally as its temperature was varied. Borie and co-workers have reported and explained very nicely similar anomalous behavior for thinner (500 Å) (110) oriented Cu2O films grown on (110) copper substrates. They showed that the epitaxial forces would cause an oxide film grown at high temperatures to contract parallel to the metal interface and expand normal to the interface as the copper cools and contracts. The oxide would expand normal to the surface in. order to keep its unit cell volume constant.

It is felt that epitaxial forces are not causing the anomalous behavior in the present work mainly because the 6000 Å of Cu2O is too thick for epitaxy to exert a meaningful force. The oxide film on the (110) copper was slightly (110) oriented but all of the Cu2O reflections behaved similarly. An additional reason to discount epitaxy is that this Cu2O film expanded upon heating from 440°-540°C. For these thick oxide films epitaxial forces do not seem to be the controlling factor; therefore, a point defect mechanism must be the cause. Changing oxidation and diffusion rates with temperature would produce various vacancy concentrations in the oxide layer and cause the spacings to vary.
New Results on the Iron-Nickel Equilibrium Diagram-The Gamma/Gamma-Plus-Alpha Boundary
Authors: Ananthanarayanan N. I. , Peavler R. J.
Published: March 2019

Solid state equilibria in iron-nickel alloys containing 0-65 at % nickel were studied by X-ray diffraction techniques, and the gamma/gamma + alpha boundary has been relocated.

Alloys were prepared by thermal decomposition and hydrogen reduction of mixed-crystal iron—nickel formates and by distilling off mercury from mixed ironnickel “amalgams,” both methods of preparation yielding equilibrium alloys in relatively short time at temperatures below 500°C, Alloys were studied at various temperatures by use of a high-temperature diffraction camera, or at room temperature as quenched from the temperature of preparation.

The study showed that the gamma/gamma + alpha boundary lies at generally higher temperatures than in previous diagrams and is concave downwards instead of upwards. The boundary shows three discontinuities which have been located to lie at approximately (a) 3 at % nickel and 760°C, (b) 35–43 at % nickel and S25°C, and (c) 50 at % nickel and 330°C. These discontinuities indicate the possible existence of three isobaric invariant three-phase equilibria, heretofore, undetected in the iron-nickel system. Further studies covering the entire range of iron—nickel alloy compositions are in progress.
Line Shape Analysis of Deformed Cu-Ge Alloys
Authors: Ahlers M. , Vassamillet L. F.
Published: March 2019

The asymmetry of diffraction peaks of deformed α-Cu-Ge alloy filings is determined by the center of gravity and Fourier coefficient method with computer calculations. It is shown that it is not possible to describe the asymmetry by a simple value that is a characteristic of the extent of the deformation and the Miller indices of the peak. Instead the asymmetry is highly dependent upon the initial arbitrary conditions for evaluation, which throws some doubt on the reliability of published twin fault and stacking fault probabilities.
Numerical Control X-Ray Powder Diffractometry
Authors: Rex R. W.
Published: March 2019

Recent development of numerical control, N/C, systems for digital X-ray powder diffractometry opens the full potential for rapid and detailed machine processing of digital diffraction data. This capability may prove to be as large an incremental technological advance as the earlier shift from film to counter detector techniques. Our N/C system has the capability of performing essentially all operations possible by manual methods. Data output is on magnetic tape and carries identification, and some of the instructions necessary for processing. The data tapes are processed by programs that (a) edit and check, (b) filter through a controlled shape high frequency filter (square, triangular, normal, etc.), (c) remove the minimum background from the diffraction pattern, (d) analyze data points close to background and test for statistical significance deleting those points within limits defined to constitute noise, (e) recognize peaks and record their position and intensity, (f) identify phases, (g) calculate phase concentrations by various methods, including internal standard and mutual standard techniques, and (h) output any desired portion of the data in a variety of digital and analog formats suitable for display, further analysis, and storage in an information retrieval system.

It is possible to record an entire diffraction pattern for a phase on two or three inches of magnetic tape. This record carries detailed peak area and shape information now missing from the ASTM reference system. Furthermore, the new magnetic tape information is directly amenable to computer processing to prepare search oriented record systems of diffraction data that can be inexpensively updated and edited. Currently, an ASTM committee is preparing a magnetic tape format diffraction pattern file. It is suggested that a second generation, computer index system be generated based on digital records of actual diffraction patterns. This type of system should prove more versatile than the old system and possibly be the only way to keep abreast of the flood of new diffraction pattern information generated from the vast number of new organic and inorganic compounds being synthesized.
The Analysis of the Light Elements in Ferrotitanium Ores and Residues of Widely Varying Composition by X-Ray Spectrography
Authors: Sanderson Benjamin S. , Yeck James A.
Published: March 2019

Ferrotitanium ores and residues may vary widely in composition. Because of this, interelemerxt effects are very large. An X-ray spectrographic method will be described for the analysis of the light elements in these ores and residues. The method uses a standard helium path Norelco spectrograph with a tungsten target tube. A KAP analyzing crystal is used for all the elements investigated. Appropriate emission lines of the elements magnesium, aluminum, silicon, calcium, titanium, and iron are measured and the results are calculated on a small computer using the empirical corrections for interelernent effects of Lucas-Tooth and Pyne. The FORTRAN program for these calculations will be given.

The problems of sample preparation, standardization, interferences and instrumental variables will be discussed. A comparison of X-ray results with chemical analysis is made.

The method is especially adaptable to automated analysis and some of the systems needed will be outlined. The method may also be modified to analyze light elements in other matrices.
Recent Advances in Quantitative X-Ray Spectrometric Analysis by Solution Techniques
Authors: Bertin Eugene P.
Published: March 2019

Usually X-ray spectrometric analyse? of samples in their original forms—solid, powder, small fabricated parts, liquid, etc.—are more rapid and convenient than analyses by any other method. Thus, the analyst is well advised to strive to analyze samples in their original form whenever practical. However, it is often necessary to reduce nonliquid samples to some other form, for example, when standards are unavailable in the original form, when the same substance is received for analysis in a variety of forms, when homogeneity or matrix effects are severe, or when an internal standard must be added. In such cases, samples and standards are often reduced to a powder, a fusion product, or a solution. If the decision is made to put the sample into solution, the many well-known advantages of solution techniques are realised, including: (1) homogeneity; (2) easy preparation of standards and blanks; (3) easy concentration, dilution, separation, and other treatment; (4) reduced matrix effects and wide choice of ways to deal with matrix effects; (5) wide choice of ways to present the specimen to the spectrometer; and (6) applicability of internal-standard, standard-addition or -dilution, indirect, absorption, and scatter methods. This paper reviews work reported since 1960 in which the specimen is presented to the spectrometer in liquid form. The review is not particularly critical and stresses experimental techniques and treatment of data rather than specific materials and results. The work is discussed in the following categories: (1) sensitivity ; (2) liquid-specimen cells; (3) interaction of primary beam and liquid specimens; (4) matrix effects; (5) indirect (association) analysis; (6) X-ray scatter methods; and (7) X-ray absorption-edge spectrometry.
Micro Fluorescent X-Ray Analyzer
Authors: Shiraiwa Toshio , Fujino Nobukatsu
Published: March 2019

A micro fluorescent X-ray analyzer with a focusing type of spectrometer has been developed to analyze samples of small amounts such as extracted inclusions or precipitates from metals or small areas in samples from 0.1 to 2.0 mm in diameter. This instrument is expected especially to analyze powder samples of small quantity because average values from such samples can be obtained and because surface conditions of the samples scarcely affect the results compared with their effect in electron probs microanalysis. A commercial X-ray tube is combined with a device of slits limiting incident X-rays, a focusing spectrometer with a Rowland circle of 4-in. radius, and a microscope of low magnification for observing the analyzing point on the samples. The wavelength range of the spectrometer with LiF and ADP analyzing crystals is from 1.20 to 9.94 Å, and, therefore, higher elements than aluminum in atomic number can be analyzed. The authors exerted their efforts to obtain the higher X-ray intensities in order to analyze smaller areas. The X-ray intensities obtained are satisfactory, except for light elements. For example, the detected X-ray intensity of pure nickel is 1650 cps with the use of a 0.1-mm diameter specimen, and that of pure sulfur is 52 cps with the use of a 0.1-ramdiameter specimen; however, with a 1-mm-diameter specimen, the intensity of pure nickel is over 5000 cps and that of pure sulfur is 1650 cps. These correspond to the intensities from 20-mm-diameter specimens of those elements when a flat-crystal spectrometer is used. The calibration curve for quantitative analysis generally varies with the sample area under analysis, but the same curves are obtained if the sample area is larger than 1 mm in diameter. Then, powder samples are analyzed quantitatively by using a plastic sample holder of 1-mm diameter and 0.3-mm depth. This instrument has good ability for microanalyzing trace elements by, for example, the ion-exchenge membrane method. The sensitivity represented is nearly 5000 cps/μg for Ni Kα from NiSO4that is soaked and dried in thin rice paper. Some applications of the micro fluorescent X-ray analyzer to precipitates in steels and corrosion products are reported.
The Effect of Surface Roughness in Polymers on X-Ray Fluorescence Intensity Measurements
Authors: Gianelos J. , Wilkes C. E.
Published: March 2019

We sought to determine how seriously surface roughness affects X-ray intensity measurements in polymers. Fourteen elements ranging from lead to silicon were added singly to fourteen batches of trans-1,4-polyisoprene. Smooth pressings of each batch were made, and intensity readings were taken (I0). Reproducibly rough surfaces were made from these by molding a square wire-mesh pattern into them, with the use of Tyler standard sieve screens. The amount of roughness was controlled by using screens of very fine to very coarse mesh. We studied the change in the X-ray intensity of the rough surfaces versus the smooth [(I/I0) × 100] with respect to: (1) the degree of roughness, (2) concentration of the added element, (3) emitted wavelength of the added element, (4) X-ray tube target material, and (5) correction for matrix effects on the intensity. We found that, at wavelengths emitted below 1 Å, intensity differences are small, regardless of which factors were varied. At wavelengths emitted above 1 Å, however, we found large differences. The intensity changes are highly dependent on roughness. Also, they become greater at the longer emitted wavelengths and with increasing concentration of added elements. Beginning with Ti Kα, losses are much higher with the use of chromium primary radiation than with tungsten. A technique of milling polyethylene into polymers with rough surfaces to provide a smooth surface is discussed.
A Study of X-Ray Fluorescence Method with Vacuum and Air-Path Spectrographs for the Determination of Film Thicknesses of II-VI Compounds
Authors: Chan Frank L.
Published: March 2019

Films of II-VI compounds have been prepared by vacuum technique for the determination of their thicknesses. Some difficulties have been experienced in preparing good quality films- The positron of the substrate in the vacuum chamber, the rate of deposition, and the temperature of sublimation are some of the factors influencing the quality of these films. For instance, films of cadmium sulfide could be prepared in the usual yellow or orange color or in colors ranging from brown to black, depending on the conditions enumerated. For energy conversion, a film of proper thickness is one of the requirements for aerospace application. Among the various methods used for the determination of the thickness of these films, X-ray fluorescence can be performed rapidly and nondestructively. After determination of thickness by the X-ray fluorescence method, the samples can be used for other determinations and for energy conversion without their efficiency's having been affected. Other physical and chemical methods have been worked out. Comparison of these methods with the X-ray fluorescence method is made. Procedures and results are presented.
The X-Ray Wavelength Scale in the Long-Wavelength Region
Authors: Burr A. F.
Published: March 2019

Recently the X-ray wavelength scale has been put on a consistent basis by the selection of the W Kα1, line to be the wavelength standard foe the whole X-ray region of the electromagnetic spectrum. To help establish this scale, four other X-ray lines, which had been measured with a precision approaching 1 ppm, were selected as secondary standards. However, since the longest of these lines is the Cr Kα2 line at 2.293606 Å, other lines whose wavelengths are less precisely known have been used for calibration purposes. The most interesting of these is the Al Kα. line, which plays an important part in the effort to connect the X-ray wavelength scale to the basic standard of length. Two other often-used lines are the Cu La line at 13.339 Å and the O Kα line at 23.62 Å. It is, however, necessary to take several steps to trace the accepted values of these lines back to the basic X-ray wavelength standard. Furthermore, the uncertainties introduced by the effects of the chemical combination and the large natural line widths limit the precision obtainable. It has been suggested that the first resonance line of the Ne K edge in the 14-Å region would overcome both of these difficulties. It has also been suggested that the highfrequency limit of the bremsstrahlung radiation would make a particularly convenient reference mark. This method is discussed here, and it is shown that the accuracy obtainable by this method is better than that obtainable by means of some commonly used reference lines.
The Application of Radioisotope Nondispersive X-Ray Spectrometry to the Analysis of Molybdenum
Authors: Langheinrich A. P. , Forster J. W.
Published: March 2019

Radioisotope excitation, solid-state detection, and multichannel pulse-height analysis have been applied successfully to the determination of molybdenum in copper and molybdenum-process intermediates. Analytical data are presented, and comparisons are made with the conventional X-ray fluorescence approach. The equipment performed satisfactorily in molybdenum plant control and shows promise for other industrial applications with the development of suitable isotope sources.
Multistep Intensity Indication in Scanning Microanalysis
Authors: Tomura Teruichi , Okano Hiroshi , Hara Koichi , Watanabe Tadao
Published: March 2019

Improvements on the semiquantitative analysis in a scanning electron-probe microanalysis will be discussed. Improvements have been attained by the development of a new content mapping attachment. By using this attachment, the X-ray intensity is indicated on a cathode-ray tube in nine steps of brightness. A discrimination operation on the intensity information can be done to help the observation of fine concentration variation in the specimen. The scanning image about an element in the specimen is displayed on the screen of the cathode-ray tube or on a paper tape by a typeout recording. The image is composed of 2500 picture elements. The brightness of each picture clement corresponds to an exponentially modulated X-ray intensity emitted from the corresponding point of the specimen surface. The correct information about the X-ray intensity to the observer is given by using this kind of modulation. In the image display on typewritten paper, the X-ray intensity is indicated with numbets from 0 to 9 according to the intensity grade. Each number is printed with an individual color to present a contour map of the element distribution. The time necessary to obtain one complete contour map is about 8.5 min.
X-Ray Double-Crystal Method of Analyzing Microstrains with BeO Single Crystals
Authors: Chikawa Jun-ichi , Austerman Stanley B.
Published: March 2019

A double.crystal arrangement was employed in the symmetrical Laue arrangement [(+n, −n) setting]. A perfect BeO crystal was used for the first crystal of the double-crystal spectrometer. To obtain a high X-ray intensity, the thickness of the crystal was made to correspond to a maximum of Pendellosung interference. A slit was pieced between the first and second (specimen) crystals to select the X-rays which precisely satisfy the Bragg condition. The slit was adjusted to avoid significant Fraunhofer diffraction. In this method, the incident beam for the specimen crystal was parallel enough to obtain intrinsic rocking curves of the specimen crystal. As an application, the method was used for determination of the senses of slight strains in BeO crystals.
An X-Ray Diffraction Study of the Aging Reaction in Two Austenitic Alloys
Authors: Abraham J. K. , Wilson T. L.
Published: March 2019

Aging processes exhibiting cluster to precipitate transitions were studied in polycrystalline line austenitic iron-base alloys with a Siemens' Guinier camera. This camera combines the Seemann-Bohlin focusing geometry with a curved-crystal monochromator arid thus maximizes the resolution of observed sidebands and the weak precipitate lines. Growth studies encompassing a cluster-size range of 15 to 70 unit cells were followed. For the systems of interest, this coincided with a variation from detectable hardness increase to a stage of maximum hardness immediately preceding precipitation, Cluster sizes were calculated on the basis of the Guinier model; variation with time and temperature permitted calculations of an apparent activation energy in the one system where decomposition was spontaneous. An iron-nickeltitanium alloy was used to study aging in a ternary system. Behavior was classic in that the cluster size present on quenching grew with aging coincident with a simultaneous hardness increase. Calculation of activation energies indicated strongly that transportation of nickel to, or iron from, the cluster was rate determining. Upon overaging, the nickel-titanium enriched clusters gave way to the hexagonal Ni2Ti phase. An iron-nickel-chromium-niobium quaternary, in addition to presenting a clustering system similar to the above ternary, showed two rather interesting phenomena. First, chromium was necessary for precipitation; the ternary ironnickel-niobium did not age. Secondly, a stable Pe2Nb Laves phase present upon quenching from 2200°F disappeared on aging in favor of nickel-niobium clusters; an incubation time for the formation of these clusters existed, and its duration was about 4 hr. An asymmetry was noted in the diffraction intensities about the (311)γ line in both systems. In the iron-nickel-titanium case, the asymmetry was only in intensity, whereas, with the iron-nickel-chromium-niobium alloys, the asymmetry existed in both intensity and position. Interpretation of these observations is made on the basis of anticipated variations in scattering factors, lattice spacings, and cluster sizes.
Provision, Suitability and Stability of Standards for Quantitative Powder Diffractometry
Authors: Jenkins Ron
Published: March 2019

Standards required for quantitative powder diffractometry are essentially of three types as shown in Table 1 - external instrument standards for the initial and long term check of instrument alignment (i.e., an “instrument” standard), external analytical standards, which are similar in composition to the specimens to be analysed, for the preparation of calibration curves for “in-type“ analysis; and internal analytical standards for the minimization of problems due to variations in specimen absorption.

The ideal equipment alignment standard should be free from preferred orientation, stable and available in large quantities, since it should serve the dual role of providing a continuing indication of the performance of a given diffractometer, as well as allowing absolute intensity comparisons to be made between different diffractometers.
Quantitative Analysis of Clay Minerals in Drilling Mud Solids
Authors: Feuerbacher D. G. , Clark R. R.
Published: March 2019

Quantitative analysis of six clay minerals commonly found in drilling mud solids is studied by x-ray diffraction using the method of internal standards. Standard clay samples are used with three internal standards to derive calibration curves from which four synthetic mud solids are analyzed. If careful sample preparation and handling are employed, reasonably accurate and reproducible results are obtained.
Quantitative X-Ray Diffraction Phase Analysis of the Oxidation of Steel by a Direct Comparison Method
Authors: Biederman R. R. , Bourgault R. F. , Smith R. W.
Published: March 2019

A direct comparison x-ray method using crystal structure Information has been developed for rapid quantitative analysis of the oxide phases present in oxidized steels. This procedure is similar to that used for the analysis of retained austenite in hardened steels and requires no external or internal standards for accurate oxide determinations. Successful application of this technique has been achieved for a variety of steel oxide mixtures and excellent correlation with microstructural analysis results has been found. Accurate determinations have been made of the volume fractions of Wustite (FeO), Magnetite (Fe3O4) and Hematite (Fe2O3) for a wide range in steel carbon content and transformation treatments. Many oxide mixtures that differ over a wide range in the amounts of each of the three oxides phases have been measured successfully. The procedure is simple, the method direct and the analysis accurate.
X-Ray Fluorescence Analysis of Portland Cement Through the Use of Experimentally Determined Correction Factors
Authors: Anderson C. H. , Mander J. E. , Leitner J. W.
Published: March 2019

Correction factors, termed α-factors, similar to those defined by LaChance and Traill have been generated by the addition of variable, known amounts of individual oxides, or other compounds, to a base cement sample and measuring the x-ray intensities of the elements of interest. The effects of all common constituents of cement on the determination of CaO, SiO2 and Al2O3 were found. Factors for rhodium and chromium primary radiation were determined and, in general, showed small but significant differences. The factors for rhodium at 50kV and 30kV were substantia11y identical. The correction factors were tested through the use of the NBS 1011- 1016 cements as reference standards to analyze the new proposed NBS cement series. The correction factors not only furnished improved calibration curves, but also allowed the determination of CaO, Al2O3 and SiO2 with an average deviation of less than 0.2% (absolute) from the provisional values furnished with the standard samples.
A Versatile X-Ray Fluorescence Method for the Analysis of Sulfur in Geologic Materials
Authors: Elsheimer H. N. , Fabbi B. F.
Published: March 2019

Nonproportionality of X-ray fluorescence intensity vs. concentration of sulfur occurs in geologic materials prepared as ground samples. Samples containing sulfur as sulfate yield higher intensities than an equivalent amount of sulfur as the Sulfide. Although the intensity of free sulfur decreases markedly during a short exposure to X-rays in a vacuum, and sulfide intensities decrease over a much longer time period, sulfate intensities show no deterioration with time.

A fusion procedure utilizing a LiBO2-Ce(NH4)2(NO3)5 flux has been developed for geologic materials to oxidize all sulfur in a multiplicity of oxidation states to a single oxidation state, namely, the sulfate. The procedure is applicable over a wide range of concentrations (0.5 - 28 wt. % total sulfur) with a detection limit of 0.01%. A suite of chemically analyzed rocks containing both sulfides and Sulfates is used for standardization.
Quantitative Nondispersive X-Ray Fluorescence Analysis of Highly Radioactive Samples for Uranium and Plutonium Concentration *
Authors: Pickles W. L. , Cate J. L.
Published: March 2019

Fluorescent x-ray energy spectra were successfully acquired from uranium and plutonium in 400:1 ratios in samples containing 2 Ci/gram of mixed fission products. The analytical system consists of a silver transmission anode x-ray tube, a low-Z scattering chamber, a magnetic ß-ray trap, a beam monitor probe, a commercial Si(Li) detector, a set of modified electronics to handle the large γ-ray overload rate, and a Computer analyzer using a higher-level language to handle data reduction.

The Computer programs used to obtain peak areas from the closely spaced uranium and plutonium (Lα 1+2) peaks were constructed to make use of knowledge of upper-edge tailing gained in this experiment. Programs are being developed to properly remove background under the uranium and plutonium peaks. Absorption effects in the larger samples have been measured using the ratio of uranium (Lℓ) to uranium (Lα) peak area and are incorporated in the data-analysis schemes. A titanium monitor probe, consisting of a fixed titanium plate near the sample, introduces a constant-area titanium K x-ray line into the spectrum. The program uses the area of this peak to correct for effects of total exciting flux, geometry, and system dead-time losses. Standard samples of various types are used to generate calibration curves from which quantitative results are obtained.

Samples are taken from dissolved high-burnup power-reactor fuel rods. The liquid sample is acidic and has a radiation level at one foot of approximately 2 R/hr ß and 300 mR/hr γ. Sample preparation involves only the evaporation of the liquid sample on a 1/2-mil polycarbonate substrate and subsequent sealing with another layer of polycarbonate film. The samples are then mounted in standard 35-mm slide-holders.

Preliminary testing on a limited number of prepared uranium and plutonium samples indicates a precision of about 1% and an accuracy of about 2%, over a range of 1 to 58 μg total mass. The samples have not yet been verified by independent chemical analysis. The system has been installed at the AEC Savannah River facility for extensive testing.
X-Ray Diffraction Residual Stress Analysis Using High Precision Centroid Shift Measurement Techniques - Application to Uranium-0.75 Weight Percent Titanium Alloy
Authors: Baucum W. E. , Ammons A. M.
Published: March 2019

The standard three-point parabola technique has been used extensively in residual stress analysis for peak location with precisions (standard deviation) of peak shift measurements in the range of 0.01° to 0.03° (20). While this level of precision produces useful data for peaks at high diffraction angles, it becomes untenable when a material with high elastic modulus is encountered whose only suitable peak falls below approximately 140° 20. Uranium-0.75 weight percent titanium alloy, which is the material of interest in this investigation, falls into this category.

A technique has been developed by which diffraction peak centroid shifts are determined with a precision of 0.002° of diffraction angle (Δ20). The method consists of step-scanning over the peak of interest to acquire data in digital form. A small Computer is then used to locate the diffraction line by calculating its centroid from digital data.

The use of a special probe consisting of four distance transdueers (LVDT) to achieve precise alignment of the specimen surface on a Siemens back-reflection stress diffractometer will also be described.

A calibration experiment was performed on uranium-0.75 titanium tensile specimens in which the X-ray diffraction response was measured as a function of various levels of applied stress in order to determine the experimental elastic moduli. It was found that repetitive analyses on a single area of a cylinder had a standard deviation on the measured diffraction centroid shift of 0.002 degree which is approximately an order of magnitude smaller than that achieved by the standard parabola fitting technique. Thus, the residual stress can be defined to a precision of ∼ 2,000 psi, as opposed to 30,000 psi, at best, were the measurements obtained by the conventional procedure.
Calculation and Measurement of Integral Reflection Coefficient Versus Wavelength of “Real” Crystals on an Absolute Basis
Authors: Brown D. B. , Fatemi M. , Birks L. S.
Published: March 2019

A method for calculation of the integral reflection coefficient of crystals of interrnediate perfection is introduced. This method can greatly reduce experimental effort for the selection and calibration of crystals, It also serves as a conceptual framework for studies of mosaic block structure and of crystal modification. Good agreement between calculated and experimental values of the integral reflection coefficient is shown for, (a) LiF crystals of two degrees of perfection, (b) elastically bent quartz, and (c) 001, 005, 006, and 007 diffraction from KAP. Zachariasen's division of crystals into two types is extended. It is concluded that the integral reflection coefficients for 200 LiF cannot be raised to the ideally imperfect limiting values.
X-Ray Production Cross Sections for Ti, Co, Ge, Rb and Sn by 16 - 44 Mev Oxygen Ion Bombardment
Authors: Chaturvedi R. F. , Duggan J. L. , Gray T. J. , Sachtleben C. C. , Lin J.
Published: March 2019

Absolute 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.
Photon Scattering from Single Crystals
Authors: Barrett Charles S.
Published: March 2019

Protons and other energetic particles when back-scattered from a single crystal emerge with anisotropic Intensity distributions. There are minima In the intensities along crystallographic directions and planes. The indices of these directions and planes and the relative intensities of these crystallographic features can be readily established by photographing the pattern of emerging particles. The patterns disclose the symmetry of the scatterer but cannot be expected to reveal the presence or absence of a symmetry center, so that the symmetry of a pattern should be related to the symmetry of one of the 11 Laue-symmetry groups, Photographs made with 50-150 keV protons are found to differ not only for crystals that belong to different Laue groups, but also for crystals belonging to the same Laue group but having different space lattices. The patterns reveal a limited amount of structural information including information on orientation, crystal perfection, and axial ratios, but not unit cell dimensions, The interpretation of patterns on the basis of particle trajectories has had major successes in the past; interpretation on the basis of diffraction has also been proposed but the inherent complexities associated, with this are very severe. Some intensity relationships observed for various crystals a-re presented, and highly simplified approximate ways of predicting relative intensities of lines are compared with the observations.
Determination of Particle Size Distribution in a Dispersion Hardened Nickel Alloy Using Small Angle X-Ray Scattering
Authors: Gould R. W. , Bates S. R.
Published: March 2019

It has been recently shown that particle size distributions can be determined from small angle x-ray scattering data. Size distributions have previously been measured in aluminum-zinc and aluminum-silver alloys containing spherical Guinier-Preston zones. Inorder to obtain the size distribution it is only necessary to calculate the Guinier radius and the Porod radius.

Dispersion hardened nickel alloys containing small spherical particles of thoria appear to be amenable to this type of analysis. A nickel-20% chromium-2% ThO2 alloy was selected for this study. The particle size distribution obtained by small angle x-ray scattering is compared with the transmission electron microscopy results found in the literature.
Kossel Line Micro-Diffraction Stum on Precipitation of Alpha from Beta in Copper Zinc Alloys
Authors: Shiwoda Gunji , Isokawa Kenji , Umeno Masataka
Published: March 2019

By the electron microprobe Kossel technique, an a-precipitate at a grain boundary of a Cu-45wt% Zn alloy was found to consist of only one crystal and the orientation relationship between the a precipitate and one of the grains beside the grain boundary was (110)β//(111)α and <111>β//<110>α. This is the same relationship as the case α a precipitates in β-phase grains. A little deviation from the exact coincidence of above orientation relationship was observed. The vacancy model for the production of a denuded zone in the same alloy was confirmed by a line scanning analyses using an electron microprobe. An effect or orientation differences was observed on the specimen current of the electron microprobe. This effect was attributed to a channelling phenomenon. The influence of ths channelling effect on quantitative analyses by electron microprobe was considered for the precipitated a-phase and matrix β-phase, and the massive a precipitates were found to consist of many crystallites having different orientations. From the lattice constant of the g-phase determined by the Kossel patterns, the concentration of zinc at the target point was obtained in good agreement with the value obtained by quantitative analyses using an electron microprobe. Thus, in some cases, the Kossel technique can be utilized for the quantitative analysis of a small portion without any corrections which are necessary In the case of electron microprobe.