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.

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.

A modification of the scanning X-ray topographic camera, is reported. The specimen and photoplate are traversed back and forth independently in two directions rather than in the same direction as in the case of Lang’s camera. The distortions of the photographs caused by geometrical arrangement can be eliminated through this construction so as to have a one-to-one correspondence. Examples of reflection photographs as well as transmission photographs are shown. Some of them are compared with those taken using Lang’s camera. The dislocation images in the reflection photographs show a good one-to-one correspondence to those in the transmission photographs. The broadening of the dislocation images in the traversing direction is discussed. The present camera is especially useful for the studies of lattice defects in the thick specimens because the reflection photographs can be easily taken.

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.

The CaNi5 system is unique among the AB5-H systems in that it exhibits three distinct hydrides (β, γ, δ) at pressures below 65 atm. (Sandrock et. al., 1982), The present diffraction study was designed to characterise these phases, only one of which has been previously studied. Nowotny (1942) gave lattice parameters for a number of AB5 (Haucke) phases including CaNi5. Takéuchi et al. (1966) gave parameters for CaNi5. Buschow (1974) reported on the entire Ca-Ni system. Oesterreicher et al. (1980) gave data on CaNi5 and CaNi5H5.5. Ensslen et al. (1981) indexed CaNi5H5.5 (γ-phase) as orthorhombic. Measurements made at NRC on one of the samples studied by Sandrock et. al (1982) and on three samples prepared at NRC are given in Table 1 together with the data from the literature. It is clear that there is a significant sample effect on the observed lattice parameters. It is well known that many AB5 compounds have a range of composition. To avoid variations due to sample effects it was decided to characterise the hydride phases on a single specimen.

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.

X-ray fractography is a new method which utilizes X-ray diffraction observation of the fracture surface for the analysis of micromechanisms and mechanics of fracture. The line broadening of X-ray diffraction profiles and the residual stress left on the surface are two of the important parameters.

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).

A set of standard samples consisting of low alloy steels, tool steels and a graphite standard was prepared carefully for measurements by polishing (down to 0.3μm alumina powder) and cleaning of the surfaces. Photographs from optical and scanning electron microscopical images were taken in order to provide information about the microstructure. The measured carbon fluorescent intensities are interpreted in view of this information as well as compared to calculated data based on fundamental parameter models. Thereby excitation by iron and carbon photoelectrons as well as secondary enhancement effects by iron K and L lines and other matrix elements were taken into account.

Results suggest that the count rates are not only a function of the total carbon content, but also of graphite segregations and to some extent of the specimen preparation procedure. Graphite particles are easily washed out and the little remaining holes may remain partially covered with carbon or filled with polishing residuals, which leads to reduced count rates.

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.

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.

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 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.

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.

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).

The diffraction of X-rays by multilayer stearate soap films has been studied as a function of (a) the number of diffracting layers and (b) the bivalent metal present. Both “Y” and “X” type structures have been built and analyzed with Al and C Kα radiation. The measured diffraction efficiency is compared with that predicted theoretically and with that obtained from a single crystal such as potassium acid phthalate.

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.

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.

This paper will discuss some of the techniques used for soft x-ray astronomy (10 kev - 0.5 kev). A more extensive treatment will be found in review papers by Giacconi, Reidy, Vaiana, Van Speybroeck and Zehnpfennig and by Giacconi, Gursky and Van Speybroeck. The earliest experiments in x-ray astronomy were performed using mechanically collimated small area ( ∼ 10 cm2) geiger tubes flown in open stabilized rockets. Subsequent improvements in sensitivity have resulted from the use of much larger ( ∼ 1000 cm2) counters and improved background rejection techniques. Important spectral information has been obtained by using gas counters which are operated as proportional counters rather than as geiger tubes and the development of the modulation collimator has significantly improved the obtainable angular resolution. The most promising new technique for x-ray astronomy is the development of grazing incidence x-ray optics .