A single-pulse X-ray diffraction (XRD) diagnostic has been developed for the investigation of shocked material properties on a very short time scale. The diagnostic, which consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, produces line-and-bremsstrahlung X-ray emission in a 40 ns pulse. The molybdenum anode produces 0.71 Å characteristic Kα lines used for diffraction. The X-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 2 mm×5 mm spot and 1° full width at half maximum angular divergence. Coherent scattering from the sample produces a Debye-Scherrer diffraction pattern on an image plate located at 75 mm from the polycrystalline sample surface. An experimental study of the polycrystalline structures of zirconium and tin under high-pressure shock loading has been conducted with single-pulse XRD. The experimental targets were 0.1-mm-thick foils of zirconium and tin using 0.4-mm-thick vitreous carbon back windows for shock loading, and the shocks were produced by either Detasheet or PBX-9501 high explosives buffered by 1-mm-thick 6061-T6 aluminum. The diffraction patterns from both shocked zirconium and tin indicated a phase transition into a polymorphic mix of amorphous and new solid phases.

The crystal structure of cloxacillin sodium monohydrate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Cloxacillin sodium monohydrate crystallizes in space group P212121 (#19) with a = 7.989 36(12), b = 10.918 09(10), c = 25.559 3(6) Å, V = 2229.50(5) Å3, and Z = 4. The crystal structure is characterized by corner-sharing chains of irregular NaO5 polyhedra along the a-axis. The carboxylate group chelates to the Na and bridges two Na cations. The coordination sphere is completed by the water molecule and a carbonyl group. The Na–O bonds are mostly ionic but have some covalent character. The bond valence sum of the Na is 1.14. The water molecule acts as a donor to the carboxylate group and a carbonyl oxygen. It is an acceptor in C–H⋯O hydrogen bonds from a methyl group and a ring carbon. The crystal structure of cloxacillin sodium monohydrate is very similar to that of the fluorinated derivative (CSD Refcode BEBCAM), reflecting the similarity of the lattice parameters. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™.

A collection of 65 formulated tablets and capsules were analyzed for phase composition by full pattern matching powder diffraction methods. The collection contained 32 of the top 200 prescription drugs sold in 2016 as well as many high-volume prescriptions and over the counter drugs from prior years. The study was used to evaluate new methods of analysis as well as the efficacy of programs designed to collect references on high volume excipients and pharmaceuticals for inclusion in the Powder Diffraction File™. The use of full pattern matching methods as well as reference pattern additions of many common excipients enabled major phase excipient identification in all formulations. This included identification of crystalline, nanocrystalline, and amorphous ingredients because full pattern matching involved the use of characteristic coherent and incoherent scatter. Oftentimes identification of the major excipients significantly aided the clean identification of the active pharmaceutical ingredients (APIs) and their polymorphic form, even at low concentrations (1–10 wt. %). Overall 93% of the APIs were identified, most through a PDF® material reference, but also through patent cross-referencing and similarity analysis comparisons.

Corrections are made to two equations and one table value in “Thermal expansion of anatase and rutile between 300 and 575 K using synchrotron powder X-ray diffraction” [Powder Diffr. 22, 352–357 (2007)].

A so-called “Vector Method” for the texture analysis of cubic materials was presented for the first time at this conference in 1976. Since then this method has been refined and applied successfully to non cubic-materials. It is shown in this paper that the Vector Method provides several advantages over series methods of texture analysis, the most important of which being the relatively small amount of experimental data which are needed for the determination of the entire crystallite orientation distribution.

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.

Molecules or ions usually exist as discrete units, in crystals of chemical compounds. Intermolecular or interionic coValent interactions are slight so the bond structure of such, solids is very similar to the pattern of energy levels in each individual molecule or ion. Simple molecular orbital theory can therefore be used to generate a qualitative picture of the energy levels in a molecule or an ion; and this picture can then be used directly to interpret X-ray emission spectra. The application of molecular orbital theory, using group theory to simplify the calculations is described for a tetrahedral unit ML4. The origin of peak shifts and of low-energy satellite peaks are rationalised. A consideration of orbital amplitudes shows that the ‘cross-over' theory of O'Brien and Skinner cannot explain the observed intensities of low-energy satellite peaks. It is suggested that the use of the M. 0. model for the interpretation of X-ray emission spectra permits far greater analytical and structural use to be made of peak shift and satellite data. Ligands can be identified even when their own characteristic emissions are not detected (e.g. oxygen and fluorine). Relative peak intensities can be correlated with atomic orbital participation in bond formation. Such information is of great interest to chemists and can often be used to identify the bonding r61e of specific orbitals (e.g. the 3d orbitals of second row, main group, elements).

A rigorous solution is developed for the correlation of the composition of mixable specimens and the fluorescent X-radiation emitted by the elements in the specimen. The instrumental modifications and treatment of the specimens are derived from the fundamental fluorescence equation.

The resultant dilution formula contains measurable quantities only. No calibration curve is required.

The theory is illustrated by some experimental data confirming the equations.

The texture of sheet metal Is best described, by means of pole figures, which are very expensive and time-consuming to prepare. About 8 to 12 hours of effort by a specially trained, and. highly skilled technician are needed to prepare each pole figure. Accordingly, pole figures are not used as extensively in research studies as they would, be if they could be obtained more easily.

A method has been developed for automatically producing pole figures by printing results directly from a digital computer. This method does not require the use of additional plotting attachments and, is therefore less expensive and time consuming than other methods. With this method, any laboratory with access to a digital computer can produce pole figures automatically.

X-ray diffraction intensities are recorded on punched tape or on punched cards and are fed into the digital computer. A computer program corrects X-ray data obtained, by either transmission or reflection X-ray techniques, maps the stereographic projection, and prints pole figures directly. The time required, to prepare an accurate pole figure is reduced from 8 to 12 hours to 20 minutes or less depending on the type of digital computer used.

The thermal transformations which take place in solid methyl-substituted ammonium perchlorates have been studied using high-temperature X-ray diffraction and differential thermal analysis techniques. In the temperature range from 20°C to their decomposition temperature (above 300°C), ammonium perchlorate and tetramethyl ammonium perchlorate undergo only one enantiomorphic phase transition, namely at 240 and 340°C (with decomposition), respectively. This I—II transition is ascribed to the beginning of the free rotation of the ClO4− ions. The rotation of the cations, however, begins below room temperature. If the symmetry of the cation is lowered by having both methyl groups and hydrogens arranged around the nitrogen (as in monomethyl, dimethyl, and trimethyl ammonium perchlorates), there is an additional enantiomorphic phase transition. This I—II transformation is ascribed to the rotation of the cations which have, in the partially substituted ions, two sets of non-equivalent symmetry axes (different moments of inertia). The temperatures of transformation are discussed in terms of the space requirements for rotation. Symmetries and cell dimensions of some modifications were determined.

The use of non-radioactive tracers for measuring certain clinically significant parameters by x-ray fluorescence analysis (XRFA) is well established at our institution (1,2). Among the technique's advantages are high accuracy, simplicity, cost effectiveness and reduced or eliminated radiation exposure to patients. One of the more versatile tracers is iodine, which has a low body toxicity and desirable chemical properties, e.g. it is easily bound to organic molecules. Other elements of interest are cesium (3), a potassium analogue of low toxicity; and xenon, the highest atomic number, stable, noble gas.

The Monte Carlo simulation method that has been previously developed and demonstrated for EDXRF analysis with annular radioisotope excitation sources is extended to systems using secondary fluorescer X-ray machines for excitation. Comparisons of the Monte Carlo predictions with experimental results indicate that the modification is valid.

The silicon diode array camera tube, recently developed for PICTURFPHONE® service, was modified to permit X-ray imaging. High quantum efficiency is attained without the use of a phosphor screen, since each photon absorbed in the silicon target generates several hundred hole-electron pairs for each keV of its energy, most of which can he usefully collected. The sensitivity and resolution are adequate to allow a continuous television display of the diffracted intensity as a crystal is oriented. Particular advantages of this technique include; high resolution (< 25 μm); electronically variable magnification; direct oscilloscope measurement of X-ray spot Intensity profiles and relative spot intensities because signal current is directly proportional to photon flux; high sensitivity in the range of 0.6 to 5.0 Å, potentially limited only "by counting statistics; integration times variable from < 1/60 second to minutes; and expected low cost, since the camera tube has no complicated electron imaging, and is directly interchangeable Mith a standard television vidicon. Applications which are described include crystal orientation and X-ray topography.

A simple two-crystal spectrometer was constructed, making use of a commercial one-crystal spectrometer. A detector attached to a 2θ-arm has been replaced by a second crystal. After adjustment, the second crystal is fixed to the 2θ-arm. The detector is placed at an appropriate position apart from the 2θ-arm. The spectrometer is operated as if it were a one-crystal spectrometer. The dispersion of the spectrometer in this mode of operation is the sum of those of the first and second crystals. Ge(220) crystals gave the best resolution which was about 3-3 eV fwhm for Cu Kα1. The strongest Intensity was observed using etched LIF crystals. The intensity was about 1/4 of that of a one-crystal spectrometer and the resolution was about 9.5 eV fwhm for Cu Kα1. The spectrometer was applied to the determination of hafnium in zirconium and sircaloy. The Zr Kα 2nd order line, which coincides with the Hf Lα1 line, was completely eliminated by successive reflections by Ge(111) crystals owing to the extinction rule and the high resolving power. The detection limit was about 7 ppm of hafnium. Another example is the separation of the As Kα2 line from the Pb Lα1 line. Arsenic in low alloy steel was determined without the correction for the well known Interference of lead. The very common interference of Cr Kβ on Mn Kα was also eliminated completely by this spectrometer. Though the spectrometer is not very suitable for a wide wavelength range spectroscopic measurement, owing to its narrow window region (about ±1°), the chemical effects on Kg spectra of sulfur in various compounds were investigated. Fine structures were found In the sulfur Kβ spectra of several thiocyanates and elemental sulfur. To observe long wavelength region spectra, the X-ray path of the spectrometer was modified to a hybrid path (vacuum and helium).

Profile changes of copper Lα (L3-V) and Lβ (L2-V) X-ray fluorescence spectra are interpreted. It is shown that the intensity of the high energy shoulder of the Cu L X-ray spectra has a relation to the intensity of the so-called ‘shake-up’ satellite in 2p X-ray photoelectron spectra; the high energy shoulder of the divalent copper La is weak for covalent compounds and strong for ionic compounds. It is also shown that the Lβ/Lα intensity ratio changes with the change of copper concentration of the analyte as well as the change of chemical state of the analyte.

Yttrium aluminium garnet, Y3A15O12– YAG, has a powder diffraction pattern that is easy to analyse in principle, but shows very interesting problems. These problems are revealed using an interactive graphics system, UNIRAS, intregated with some of the usual procedures for crystallographic data processing. For example, indexing with the APPLEMAN procedure is improved when the high-angle peaks are properly identified, and the cell parameters then refine to a high precision. Iterations between refinements and graphical analysis allows the operator to identify even some of the very weak peaks in the pattern. Using the peak positions from the refinement, the experimental data can be analyzed for instrumental aberrations and corrections can be applied to improve the accuracy of the cell parameter.

Two high-temperature X-ray diffraction cameras are described which have been employed at Battelle to determine thermal expansion of metals and ceramic materials. Specimen preparation and temperature measurement and control are described. Lattice-parameter data vs. temperature are presented for uranium, uranium dioxide, and magnesium oxide.

The use of polarized x-rays to excite fluorescence spectra with decreased backgrounds and improved detection limits is reaching a mature state of development. With bulk, low-Z specimens, polarized x-ray sources have produced detection limits which are ~℩ to 3 times lower than are obtained with the best unpolarized photon sources. Based upon experience and the known properties of larger solid angle geometries, further significant to dramatic improvements are anticipated.

The success of a diffraction experiment often depends on the proper preparation of the sample under study. Many different methods of sample preparation have been devised for many different purposes. A survey was conducted to collect together many of these methods, and the results are reported in this paper.

A new method is proposed for evaluating rapidly the diffraction peak broadening by using the standard deviation of a Gaussian function approximating the diffraction peak. This value, called the Gaussian curve parameter (GCF), is given by

The use of the GCP permits rapid and nondestructive measurement of plastic strain and hardness of quenched and tempered steels with an automated X-ray stress analyzer using a personal computer. The GCP increases with increasing hardness of quenched and tempered steels. It also increases with increasing plastic strain by stretching. Furthermore, the GCP can be used for rapidly evaluating hardening of quenched steels.