The status of the solid materials and mineralogical and petrological results of the Stardust mission to comet 81P/Wild 2 are presented. This mission became the first successful sample-return mission since the Apollo project. This time the challenges were much less related to the availability of state-of-the-art analytical capabilities. Still, dedicated tools had to be developed to manipulate the samples that were all firmly embedded in the tracks they made when decelerating in the silica aerogel tiles of the collector. The comet particles were loosely bonded aggregates that shed their grains along the entire length of these tracks. It appears that most of the original comet minerals survived but interactions of debris with melted aerogel occurred and new minerals were made, adding to the incredibly, and unanticipated, diversity of the comet minerals, including some that so far were known only in meteorites. The latter alone showed that transport distances in the solar nebula extended all the way out to beyond Pluto into the Kuiper Belt of icy, comet-like, bodies. The full extent of the scientific yield of this mission is still unknown, promising but stressing current models of the formation of solar systems.

Methods using X-ray fluorescence have been developed to identify cometary material captured in aerogel during the NASA Stardust mission to Comet 81P/Wild 2. These analytical methods are necessitated by the levels of trace contaminants present in the aerogel. The cometary material disaggregates during deceleration in the aerogel, so fluorescence mapping of the entire track (which can be several millimeters long) is necessary. Distinguishing those pixels which have cometary material and aerogel from those which have only cometary material can be very challenging. We have chosen a “dual threshold” method, with some pixels clearly having only aerogel (plus contaminants) and other pixels clearly having cometary and aerogel material. Between these two threshold levels is a set of pixels which cannot be easily ascribed to one or the other. By leaving these pixels out of the analysis, the estimate of cometary material is improved.

A practical description of the mathematics required to implement the hexagonal grid and spiral trace pole figure data collection schemes is presented. Applying the concepts of stereographic and equal area projections with geometry, spreadsheets were created to calculate the angular settings of the goniometer. Using the generated settings, the hexagonal grid and spiral trace schemes were programmed into the existing X-ray software and employed to collect data for a sample of aluminum foil. The resulting (111) pole figures were similar to those collected with the conventional 5°χ×5°ϕ grid. The hexagonal grid has been shown by others to reduce the number of data points and time needed to complete a pole figure, while providing equal area sampling. Although not optimized, the spiral method was also investigated as another alternative to the 5°χ×5°ϕ grid.

X-ray and neutron fiber diffraction has been used to study cellulose as it is converted from its naturally occurring crystal phase, cellulose I, to an activated crystal phase, cellulose IIII, by ammonia treatment. The detailed crystal structures determined for cellulose Iβ, an intermediate ammonia-cellulose I complex, and cellulose IIII, reveal a structural transition pathway: hydrogen bonded sheets of chains in cellulose Iβ slip with respect to each other to accommodate the penetrating ammonia guest molecules in the intermediate complex. On evaporation of ammonia from the intermediate complex, there is a relative small change in chain packing as an inter-sheet ammonia bridge is replaced by an inter-sheet hydrogen bond in cellulose IIII. When cellulose IIII is heated it converts back to cellulose Iβ. Both ammonia-cellulose I and cellulose IIII have extended chains of cooperative hydrogen bonds in relatively open crystal structures that may add to their susceptibility to rapid change.

This study focuses on characterization of an (Al,Cr)3Ti alloy processed together with titanium powder by reactive mechanical milling (RMM) to produce an ultrafine grained intermetallic alloy matrix with in situ carbide and hydride phases formed during processing. Observations of X-ray scattering as RMM processing time increases show severe broadening of matrix diffraction peaks, accompanied by the appearance of diffraction peaks resulting from the formation of very small crystallites of TiC and TiH1.92 phases with increasing volume fractions, and finally, increasing background intensity as the crystallite size of the matrix phase decreases to ∼2 nm. Estimates of phase volume fractions were made by the direct comparison method, along with crystallite sizes by Warren–Averbach peak profile analysis. The general increase in background intensities has been attributed to random static displacements of the large fraction of atoms located within the grain boundary regions. Further, it has been concluded that the matrix material with a crystallite size of a few nanometers has about half the atoms in statically displaced positions defining the boundary regions. The results argue that background intensity changes should not be ignored and are useful in interpreting scattering from these nano-scale materials.

A novel type X-ray detector, called PILATUS, has been developed at the Paul Scherrer Institut in Switzerland during the last decade. PILATUS detectors are two-dimensional hybrid pixel array detectors, which operate in single-photon counting mode. PILATUS detectors feature a very wide dynamic range (1:1 000 000), very short readout time (<3.0 ms), no readout noise, and very high counting rate (>2×106counts/s/pixel). In addition, a lower energy threshold can be set in order to suppress fluorescence background from the sample, thus a very good signal-to-noise ratio is achieved. The combination of these features for area detectors is unique and thus the PILATUS detectors are considered to be the next generation X-ray detectors. The basic building block of all the detectors is the PILATUS module having an active area of 83.8×33.5 mm2. The PILATUS 100K is a complete detector system with one module. PILATUS detector systems can have other configurations, including large area systems consisting of 20 to 60 modules that can cover up to an area of 431×448 mm2. Such large systems are mainly used for macromolecular structure determination, such as protein crystallography and small angle X-ray scattering. The PILATUS 100K detector can be easily adapted to many systems; the single-module detector is integrated to an in-house X-ray diffraction (XRD) system. Examples of XRD measurements with the PILATUS 100K detector are given.

Synchrotron-based X-ray microbeam measurements were performed on silicon-on-insulator (SOI) features strained by adjacent shallow-trench isolation (STI). Strain engineering in microelectronic technology represents an important aspect of the enhancement in complementary metal-oxide semiconductor device performance. Because of the complexity of the composite geometry associated with microelectronic circuitry, characterization of the strained Si devices at a submicron resolution is necessary to verify the expected strain distributions. The interaction region of the SOI strain extended the SOI film thickness from the STI edge at least 25 times. Regions of 65-nm-thick SOI less than 3 μm wide exhibited an overlap in the strain fields because of the surrounding STI. Microbeam mapping of arrays containing submicron SOI features and embedded STI structures revealed the largest out-of-plane strains because of the close proximity of superimposed strain distributions induced by the STI.

Structural development of BPDA-PPD polyimide thin film has been investigated by in situ grazing incidence X-ray diffraction at the BL24XU beamline of the SPring-8. Optimizing the sample shape, two-dimensional images were measured successfully without sacrificing angle resolution. It has been clearly shown that the crystallization first begins in the in-plane direction, at the curing temperature of 180 °C, in which the periodic structure of the molecular chain axis (c axis) is developed. The crystallization in the surface normal (out-of-plane) direction is observed later, at the curing temperature above 300 °C. A slight increase of the d spacing of the c axis during heating process has been observed, suggesting the stretching of the contracted molecular chain in accordance with the curing process. In the cooling process, the decrease of the d spacings for a and b axes was considerable, which indicates thermal expansion of the crystals at high temperatures. The increases in the peak intensities during the cooling process have been observed, which indicate the d spacing of each axis becomes close to the equilibrium value to produce higher periodicity.

Fiber diffraction data have been obtained from Narcissus mosaic virus, a potexvirus from the family Flexiviridae, and soybean mosaic virus (SMV), a potyvirus from the family Potyviridae. Analysis of the data in conjunction with cryo-electron microscopy data allowed us to determine the symmetry of the viruses and to make reconstructions of SMV at 19 Å resolution and of another potexvirus, papaya mosaic virus, at 18 Å resolution. These data include the first well-ordered data ever obtained for the potyviruses and the best-ordered data from the potexviruses, and offer the promise of eventual high resolution structure determinations.

The development of a tool called the Service Load Factor (SLF) for railway tapered roller bearings using residual stress and retained austenite data is presented. Case-carburized tapered roller bearings used in the railroad industry are manufactured with a dual-phase microstructure that consists primarily of tempered martensite and retained austenite. The retained austenite phase is metastable, and will transform to martensite with sufficient thermal or mechanical energy during service. The increase in surface volume because of transformation, and the subsequent increase in compressive residual stress could indicate the onset of certain failure modes, including fatigue spalling. In addition, retained austenite transformation can lead to an increase in bore diameter, which could result in a loss of fit on the axle journal. Several bearing inner races with various service histories were measured with a Siemens X-ray diffractometer using chromium radiation. Results indicated that the transformation of retained austenite and resultant increase in compressive residual stress are interrelated with load and rolling cycles. Results indicate that the SLF is a useful tool that correlates well with current Association of American Railroads failure criteria.

A specially designed specimen holder employing a beryllium dome has been fabricated for collection of X-ray diffraction (XRD) data from highly reactive materials. The specimen holder has a robust O-ring type seal (<10−9Torr) and no observed intensity artifacts in the 1° to 150° 2θ range. The design also minimizes specimen displacement errors and allows for analysis of both powders and bulk specimens (i.e., pellets). The simple design makes for straightforward assembly of the holder within the confines of a glove box. XRD analysis of hygroscopic LaBr3 powders collected with this holder are suitable for Rietveld structure refinement, yielding unit cell lattice parameters of a=7.9703(6) Å and c=4.5122(6) Å; cell volume=248.44(6) Å3; Rp=7.70%.

Dislocation model of strain anisotropy is presented. The dislocation theorem of strain broadening is suggested which means that strain broadening can only be caused by dislocation-type lattice defects. Based on this theorem strain anisotropy is modeled and accounted for by assuming that strain broadening is caused by dislocations or dislocation-type lattice defects. The effect of strain anisotropy is summarized in hkl dependent dislocation contrast factors, which can be either averaged over the permutations of hkl indices or are different for each different reflection. The dislocation model of strain anisotropy provides a powerful tool to analyze slip activity, Burgers vector populations, and plasticity on the basis of line profile analysis.

In situ X-ray diffraction was used to study the interactions of the PNNL G18 fuel cell sealing glasses with the oxides that form on candidate interconnect alloys and with the ebrite alloy. Experiments under 4% hydrogen and air at temperatures up to 1000 °C showed that the sealant reacts rapidly with alumina and chromia, but not with NiO. The crystallization of the high-CTE phase BaCrO4 was noted for G18 in contact with chromia or ebrite under air, but reducing conditions inhibit the crystallization. The reactions in all cases begin within a few hours at temperatures above 800 °C and go to completion or near completion after ∼12 h.

Rhombohedral-cubic transformation in Bi2Te3 doped-Pb1−xGexTe alloys is presented. Samples of Bi2Te3 doped Pb1−xGexTe were prepared by powder metallurgy approach. These powder samples were examined by high-temperature X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive spectroscopy. A bulk (pressed powder) cylindrical specimen was used for dilatometery characterizations. According to the XRD examinations it seems that upon increasing the temperatures a continuous transformation occurs from the rhombohedral to the cubic phase, accompanied by the formation of a small amount of the phase Ge0.74Pb3.26Te4.

Quantitative comparisons between patterns from PDF-4 and experimental data using the Integral Index method are presented. The software integrated into the PDF-4 (DDView+) provides the ability to calculate fully digitized diffraction patterns for all 272,232 entries (PDF-4+ 2007). To provide a means of quantitative comparison between entries in the Power Diffraction File (PDF) and experimental data obtained in the laboratory, data filtering using Boolean logic has been used to reduce the size of the comparison set. Within this comparison set, we have used the Integral Index method to provide quantitative comparisons between digitized patterns obtained from the PDF-4 and experimental data. The quantitative aspects facilitate total pattern matching, that is, selecting the pattern in the PDF-4 that most closely matches input experimental data. Several examples will be used to illustrate the pattern matching process and the utility of this approach will be examined.

A specimen containing nanograms of sulfur, calcium, and 3d transition metal elements was measured by incident X-ray beams of various sizes restricted by a waveguide placed in a portable TXRF spectrometer. The signal to background ratios of spectra decreased with an increase in incident X-ray beam size. The portable spectrometer was also applied to rainwater and a specimen containing antimony and rare earth elements. Nanograms of elements in these specimens were detected by K-line or L-line excitation.

Results from Monte Carlo simulations of two-dimensional projections for a simple real sample (an aluminium cube with a cylindrical hole filled by air or steel) in a realistic experimental environment are presented. A meaningful comparison with measurements was therefore possible. Coherent and incoherent scattering as well as excitation of fluorescent radiation are accounted for; multiple sequences of these interactions are followed up to a selectable order. Such simulations are important aids to modern metrological applications of computed tomography where the dimensional accuracy of hidden or inaccessible components of work pieces is determined. The complex process requires a high level of optimization of the instrumental parameters for each sample type whereby the accurate simulation of the physical interactions between X-rays and the sample material is a supplement and alternative to time consuming measurements.