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.

An additional statistical calibration for the Bruker D8 Discover microdiffractometer is necessary to obtain accurate reproducible 2θ data for cell-refinement work. This new approach uses a graphical mapping method of the 2θ error versus the location of a selected diffraction peak on the detector surface to describe the separate roles of different calibration procedures (rebiasing, flood field, and spatial corrections) and parameters (sample-to-detector distance, x-y center coordinate) in minimizing the error. Optimized parameters are used to obtain the lowest achievable Δ2θ with this setup. Intensity error relative to the position of the diffracted line on the detector was found to be consistent at up to 20% and could not be reduced using any of the investigated techniques and parameters.

Four new compounds with general formula CdI2-2(NH2-PhX) (Ph represents phenyl radical; X represents Cl or H atoms) were obtained and characterized. Two of them, bisaniline diiodidecadmium(II) — CdI2⋅2[NH2–C6H5] {1} and bis(2-chloroaniline) diiodidecadmium(II) — CdI2⋅2[NH2–C6H4Cl] {2}, crystallize in monoclinic system, whereas another two, bis(3-chloroaniline) diiodidecadmium(II) — CdI2⋅2[NH2–C6H4Cl]{3} and bis(4-chloroaniline) diiodidecadmium(II) hemi(4-chloroanilate) — CdI2⋅2[NH2–C6H4Cl]½[NH2–C6H4Cl] {4}, crystallize in triclinic system. The investigated compounds, from chemical point of view, are similar to the so-called cisplatin—a compound used as a chemotherapy drug to treat many types of cancers. Their syntheses and results of X-ray powder diffraction studies at room and elevated temperatures are described in this paper.

Preferred orientation or texture is a common feature of experimental powder patterns. The mathematics of two commonly used models for preferred orientation—the March-Dollase and the generalized spherical-harmonic models—is reviewed. Both models were applied individually to neutron powder data from uniaxially pressed molybdite (MoO3) and calcite (CaCO3) powders in Rietveld analyses, as well as the as-received powders. The structural refinement results are compared to single-crystal structures. The results indicate that reasonable refinement of crystal structures can be obtained using either the March model or generalized spherical-harmonic description. However, the generalized spherical-harmonic description provided better Rietveld fits than the March model for the molybdite and calcite. Therefore, the generalized spherical-harmonic description is recommended for correction of preferred orientation in neutron diffraction analysis for both crystal structure refinement and phase composition analysis. Subsequently, the generalized spherical-harmonic description is extended to crystal structure refinement of annealed and the aged polycrystalline Ni-rich Ni50.7Ti49.30 shape memory alloys.

In this work synchrotron radiation X-ray diffraction technique was successfully applied for the analysis of pigments found in excavation at Carriqueo rock shelter, Neuquén, Argentina. The pigment samples of orange, red, and brown shades were collected from different levels of this archaeological site and compared with a suspected source of provenance (La Oficina creek). X-ray diffraction patterns of several yellowish, reddish, and red pigments showed the presence of haematite, goethite, kaolinite, and quartz. The majority of Carriqueo collected samples belonged to the same group of the suspected source, having haematite and quartz as main crystalline phases. The results indicate that the raw material from La Oficina is the source of most of the pigments found at Carriqueo. The present work helps us to understand the strategy of supplying raw materials by human groups in the North Patagonia region.

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.

Crystal structure of Li2SrSiO4 was reinvestigated by laboratory X-ray powder diffraction. The title compound was trigonal with space group P3121, Z=3, unit-cell dimensions a=0.502 281 (4) nm and c=1.245 520(8) nm, and V=0.272 129(3) nm3. The initial structural model was derived by the direct methods and further refined by the Rietveld method. The maximum-entropy method-based pattern fitting (MPF) method was used to confirm the validity of the structural model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The final reliability indices calculated from MPF were Rwp=8.04%, S=1.22, Rp=6.01%, RB=1.50%, and RF=0.66%. Atomic arrangements of the final structural model were in excellent agreement with the three-dimensional electron-density distributions determined by MPF.

X-ray powder diffraction data for five new bismuth yttrium gadolinium oxide compounds synthesized by solid state reaction method are reported. The unit cell dimensions were determined from X-ray diffraction methods, using CuKα radiation, and evaluated by indexing programs. The cubic phase was the sole crystalline phase detected by X-ray diffraction analysis in Bi0.88Y0.06Gd0.06O1.5, Bi0.88Y0.08Gd0.04O1.5, Bi0.82Y0.09Gd0.09O1.5, Bi0.82Y0.12Gd0.06O1.5, and Bi0.82Y0.06Gd0.12O1.5 samples with lattice constants of a=5.5371(1) Å, a=5.5368(1) Å, a=5.5303(2) Å, a=5.53487(8) Å, and a=5.5279(1) Å, respectively. The results are in good agreement with those reported for bismuth yttrium oxide (Bi0.75Y0.25)O1.5 (PDF 01-084-1450).

A computer program is presented that allows for the merging of diffraction patterns collected at multiple positions on the Powder Diffraction beamline of the Australian Synchrotron. It is also generally applicable to detector systems based on other modular detectors. The program allows for the interpolation of data to a constant 2θ step size and to normalise intensities to beam current and/or monitor count rate.

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.

X-ray powder diffraction data, unit-cell parameters, and space group for a novel platinum-based anticancer complex cis-[diiodo(1R,2R)-1,2-diaminocyclo-hexane-κN,κN′] platinum(II), Pt(C6H14N2)I2, are presented [a=14.048(4) Å, b=7.588(3) Å, c=11.502(4) Å, β=98.446(5)°, space group C2, cell volume=1212.80 Å3, and Z=4]. All measured lines were indexed and are consistent with the C2 space group. No detectable impurities were observed.

New XRD total pattern fitting software MSTRUCT was used to study the microstructure of magnetron-deposited TiO2 thin films. MSTRUCT is an extension of the FOX program for structure determination from powder diffraction data. MSTRUCT makes corrections for refraction and absorption, residual stress, and preferred orientation that are necessary for thin-film analysis using the parallel-beam geometry and an asymmetric detector scan with small angles of incidence. The program also corrects for crystallite size broadening in terms of log-normal distribution, two models of strain (phenomenological and dislocation models), as well as the influence of stacking faults in the most common cubic and hexagonal structures. The microstructure results obtained by this study show that during crystallization of the amorphous TiO2 films, tensile stresses were generated resulting in anisotropic shifts of diffraction peaks. This was confirmed by in situ crystallization and direct stress measurements. The consideration of the stress effect in terms of the weighted Reuss-Voigt model improved the fits significantly. The stresses were found to depend systematically on the TiO2 film thickness, and their values determined by total pattern fitting agree well with the values measured directly by XRD stress analysis.

Reported results for four new cubic compounds NdMMgMn2O6 (M=Li, Na, K, Cs) are questionable and cast doubt on the existence of such compounds. The lattice constants and relative intensities are essentially the same regardless of the nature of M; the X-ray diffraction patterns may be indexed with the lattice constants divided by √8, which result in much better figures of merit and a=0.3861 to 0.3883 nm, close to the subcell parameter of non-stoichiometric pseudocubic NdMnO3.