Curved Position Sensitive Detector Research Articles

Recent advances in high-resolution X-ray diffractometry applied to nanostructured oxide thin films: The case of yttria stabilized zirconia epitaxially grown on sapphire

The investigation of nanostructured oxide thin films using high-resolution X-ray diffraction (XRD) is considered. Because of the small amount of matter deposited and significant defect densities, such oxide thin film structures can be considered as imperfect materials that require specific data acquisition and data analysis methods. Fast reciprocal space mapping is carried out using a diffractometer based on an 18 kW X-ray source, a four-reflection monochromator and a curved position sensitive detector. In order to extract quantitative information concerning the microstructure of the films, an approach is developed that combines a microscopic modelling of dimensional effects (crystallite or island shape, size and size distribution) with a phenomenological description of lattice disorder. Within this approach, simple analytical expressions or expressions implying a simple Fourier transform, can be derived for the XRD intensity distribution in the direction perpendicular to the film surface and parallel to it. Profiles exhibiting damped and/or broadened fringes and profiles exhibiting a two-component line shape can be simulated. Parameters of primary interest, such as the island thickness, thickness distribution function, island in-plane dimensions and the distribution function of the dimensions, the level of disorder, the disorder correlation length and the spatial distribution of disorder, can be extracted. The applicability of the model is illustrated with yttria stabilized zirconia films epitaxially grown on sapphire by sol–gel dip-coating.

Application of In-Process X-ray Powder Diffraction for the Identification of Polymorphic Forms during Batch Crystallization Reactions

An on-line X-ray diffraction system capable of monitoring and identifying the polymorphic form of organic materials crystallized during batch crystallization processes is described. The overall system comprises a conventional X-ray source, monochromator, collimator, slits, curved position sensitive detector, and a flow-through analysis cell together with the electronics and the data acquisition software. The cell enables X-ray diffraction data to be recorded from crystals suspended within a slurry pumped to and from a batch crystallizer via an external temperature controlled sampling loop. The system is validated via benchmark crystallization studies of urea, l-glutamic acid and monosodium glutamate. The system was found to have a performance consistent with a lower detection limit of ca. 1% wt % of crystals and to be able to follow polymorphic transformation during representative crystallization processes. A forward look to the further development of the system is provided.

Fast x-ray scattering measurements on molten alumina using a 120° curved position sensitive detector

Fast x-ray scattering measurements on molten alumina were performed on the H10 beam line at the DCI Synchrotron of LURE (Orsay, France). A high-temperature chamber with a levitation device was coupled with the four-circle goniometer of the beam line. A 100 W CO2 laser was used to melt the sample and the temperature was measured using an optical pyrometer operating at 0.85 μm. Usually, measurements of the total structure factor S(Q) on molten materials are performed using a fixed detector scanned over an angular range. In this work, in order to reduce the total scan duration, x-ray scattered intensities were measured with a 120° position sensitive detector (INEL CPS120). We performed several measurements with different acquisition times varying from 10 s to 5 min. In 5 min it was possible to obtain a good determination of S(Q) with a usable signal up to the Q range limit (13 Å−1). The intensity was comparable with a 1 h measurement with a NaI (Tl) scintillator scanned over the 120° 2θ range. On reducing the counting time the statistics are degraded and the data are noisier, especially in the high Q region. Nevertheless, even with 10 s, the S(Q) data remain usable and give good results. Performing the Fourier transformation of S(Q), we obtain similar reliable pair-correlation functions with both 5 min and 10 s acquisition times.

Shape, size and composition of mullite nanocrystals from a rapidly sintered kaolin

The characteristics of mullite crystallites from a kaolin raw material were determined at the early stage of crystallisation by X-ray diffractometry. The equipment was a Debye–Scherrer system equipped with a curved position sensitive detector. We measured the size and shape of mullite crystallites in relation to the temperature (1100–1150°C) and the temperature rate (3–20°C/min). In particular, a temperature rate influence was found on crystallites anisotropy. This result was satisfactorily correlated with TEM observations of sintered materials. The mullite cells constants were also measured, they vary significantly with sintering conditions. Cell constants were correlated with mullite stœchiometry using the Cameron relationship. Results indicated a narrow composition domain (62–65% Al2O3) for all thermal cycles. In each case, the orthorhombic phase was identified, in spite of the low temperature range studied and the relatively high alumina content.

The refinement of a tetragonal phase of WO3 using a novel PSD high temperature X-ray powder diffractometer

The atomic positions of the tetragonal phase P4/nmm of WO3 were refined using a novel high-temperature X-ray powder diffractometer with a curved position sensitive detector (PSD). In addition, the lattice parameters of WO3 from room temperature to 1200K have been measured. Comparison is made with the results obtained by neutron powder diffraction.

Profile Analysis in Asymmetric Powder Diffraction with Parallel Beam Geometry and Curved Position Sensitive Detector

Profile Analysis in Asymmetric Powder Diffraction with Parallel Beam Geometry and Curved Position Sensitive Detector

The Use of Brilliance in Powder Diffraction: Towards High Resolution Kinetic Studies

The initial design of a high count rate curved linear position-sensitive detector for high-resoln. powder diffractometry is described in conjunction with the advantages afforded by higher flux sources. The specifications of the new detector are count rates in excess of 106, an angular resoln. of 0.030, or sufficient energy resoln. to reject the 3rd harmonic from the incident beam and angular aperture of ?60�. The new curved position sensitive detector has the potential to improve on the step scanning data collection times by a factor of 1000, because there is no dead time in driving and all data points in the powder diagram range can be collected simultaneously. [on SciFinder(R)]

Reflection Asymmetric Powder Diffraction with Flat-Plate Sample using a Curved Position-Sensitive Detector (INEL CPS 120)

The reflection flat-sample asymmetric geometry is an attractive set-up for powder diffraction measurements, as compared to either conventional Debye–Scherrer or symmetric Bragg–Brentano geometries. Combined with grazing- or fixed-incidence-angle X-rays, it is suitable for surface-structure or thin-film texture analysis. Furthermore, it allows curved position-sensitive detectors to be used for in situ experiments. In this paper, the major systematic error sources in connection with this geometry are reviewed. It is confirmed that experimental linearization of the curved position-sensitive detector and sample positioning have to be very carefully performed. Simple and automatable procedures are proposed. Then, it is shown that peak-location accuracy leads to satisfactory cell-parameter determination as checked by the use of a silicon international standard reference sample and that structure refinement by the Rietveld method can be performed in very good conditions, as observed with an NaBi2Sb3O11 compound.

A comparison of laboratory, synchrotron and neutron diffraction for the real time study of cement hydration

The use of real time powder diffraction for the study of cement hydration is presented. Three techniques are described: laboratory X-ray diffraction with a linear position sensitive detector, neutron diffraction with a curved position sensitive detector and energy-dispersive powder diffraction with a synchrotron source of X-rays. Data collected during the hydration of a triclinic form of tricalcium silicate are used to illustrate the methods of data capture and analysis for each of the three techniques. The rate of tricalcium silicate depletion is presented for each case and an attempt at a quantitative comparison of the three techniques is made.

Study of CuAlBe Shape Memory Alloy by X-Ray Diffraction

A complete study of Ms-30 o C polycrystalline CuAlBe shape memory alloy is made by X Ray diffraction using a texture goniometer equipped with a curved position sensitive detector. Austenite and martensite unit cells parameters are measured; Measured indexes and orientation of the habit plane are compared to those expected by the lattice parameters. Austenite after extrusion shows a strong fiber texture, volumic fraction of austenite and martensite are measured according to the deformation. Internal deformations of three grains of a Ms-100 o C CuAlBe sample are followed during their macroscopic deformation

Structural change of GeO2 under pressure

Pressure-induced amorphization of α-quartz type GeO2 was studied with a newly developed X-ray diffraction system which consists of a 4-circle goniometer and a curved position sensitive detector. Single-crystal diffraction was measured under pressurs up to 7.3 GPa at room temperature in order to investigate pretransitional phenomena. Diffraction intensity and line width of the diffraction profiles showed no remarkable change up to 5.9 GPa. However, no sharp diffraction line was observed at pressures over 6.5 GPa. The bulk modulus at 0.1 MPa and its pressure derivative of α-quartz type GeO2 were determined to be K T =32.8(3.3) GPa and K′ T =6.0(2.0), respectively. In situ microscopic observations of the amorphization transformation was also performed. The large volume change due to amorphization was observed and estimated to be about 10%.

小型高輝度Ｘ線発生装置を用いた薄膜Ｘ線回折装置の開発

An X-ray diffractometer newly designed for thin film analyses is consisted of a compact X-ray generator with high loaded power rate to a small focus, a curved position sensitive detector and K-axis type 4-circle goniometer. The diffractometer enables measurements of thin film samples for electronic devices, e.g. rapid pole figure measurements of thin film samples and depth-sensitive measurements of multilayer thin films. A preffered orientation analysis of Co-Nb-Zr films for VTR core and a crystallinity analysis of multilayer films for circuit board were performed by using this apparatus.

Ab Initio Structure Determination of Lithium Diborate Hydrate, from X-Ray Powder Diffraction Data Collected by Means of a Curved Position Sensitive Detector

Ab Initio Structure Determination of Lithium Diborate Hydrate, from X-Ray Powder Diffraction Data Collected by Means of a Curved Position Sensitive Detector

特集 粉末回折法の新しい展開 １１． 湾曲型Ｘ線位置敏感検出器（ＰＳＤ）と動的構造研究

Time-resolved observations of phase transitions and solid reactions have been undertaken by angular dispersive powder diffraction at high temperature and pressure using the curved position sensitive detector (PSD) . The PSD streamer mode has a great advantage for the in situ observations of the structure changes within a few seconds because of high photon count efficiency of more than 70% and high angular resolution of 0.06° in 2θ.A Computer Aided Measurement And Control (CAMAC) System was applied to the time-resolved measurement of the diffraction intensities. An ADC having a 450MHz fast converter and histogram memory were installed in the system. The in situ observation of the pressure-induced amorphization of GeO2 using diamond anvil pressure cell and kinetic studies of dehydration of alkaline earth hydroxides at high temperature are presented in this paper.

Time-resolved X-ray powder diffractometry as a complementary thermal analysis method

The use of a conventional X-ray diffractometry together with curved position sensitive detector (PSD) allows for a complete diffraction pattern to be recorded as a function of time and temperature, so that transformations in the solid state can be traced sequentially. In this way, this technique can be regarded as complementary to the conventional thermal analysis methods, as thermogravimetry and differential scanning calorimetry. Three applications are described: the thermal decomposition of a cadmium hydroxide nitrate, the phase transformation of the dicesium cadmium tetraiodide and the investigation of microsturctural properties as a function of temperature.

Time-Resolved Observations of Solid Reactions and Structure Transitions using a PSD, An SSD and Computer Aided Measurement and Control

AbstractFor time-resolved diffraction studies under high temperature and/or high pressure, we designed a new diffractometer incorporating a curved position sensitive detector and tested the rapid intensity measurement and the resolution of the angular dispersive diffraction. The diffraction profiles were compared with those from energy dispersive diffraction. Rapid intensity collection has been carried out with a CAMAC module. A curved position sensitive detector with a 120° working angular region was installed on the off-centered four circle diffractometer. Only a few seconds were needed to obtain a whole powder diffraction because of the extremely high counting efficiency due to the streamer mode.Time-resolved observations of the dehydration reactions of Mg(OH)2 and Ca(OH)2, have been undertaken by angular dispersive and energy dispersive x-ray powder diffraction at high temperature. The in situ observations of the dehydration process provide kinetic information, such as the reaction rate, the apparent activation energy and the dehydration mechanism.

In-Situ Strain Measurement Via X-Ray Diffraction

ABSTRACTA high speed x-ray diffraction system has been built around a Curved Position Sensitive Detector. This system has a hot/cold stage in a modified vacuum chamber to allow for control of the ambient gas mix while in-situ x-ray diffraction spectra are acquired. We have used this system to measure the strain in Al/Cr/SiO2 structures after abrupt changes in temperature. The good adhesion afforded by the Cr layer combined with the large difference in the thermal expansion coefficients of the Al (≃25×10−6/°K) and the quartz (≃0.5×10−6/°K) components make this an ideal sample for demonstrating the capabilities of this system. In-situ resistivity measurement provides an independent indication of the changes in the sample.

Powder diffraction facilities at Daresbury Laboratory

X-ray powder diffraction measurements using synchrotron radiation are currently being carried out on three experimental stations on the SRS at Daresbury Laboratory. Station 9.1 contains a general purpose powder diffractometer for angular dispersive measurements. The instrument is sited on the wiggler beamline, which provides radiation with a critical energy of 12 keV. A Si(111) water-cooled, channel-cut monochromator gives useful flux over an energy range from 6 to 30 keV. A cryostat and furnace are available for experiments requiring special environments, while a curved position sensitive detector can be used for time-resolved measurements. The wiggler white beam is employed on Station 9.7 for energy dispersive powder diffraction experiments. Various sample stages for kinetic experiments are in use on this station, and examples are shown of recent high-pressure work. A new high resolution powder diffractometer has been built and commissioned on Station 8.3, using bending magnet radiation. The diffractometer is based on the Parrish and Hart design, in which long, parallel foils are used to define the angular divergence accepted by the detector. In this way, large synchrotron beam cross sections can be employed while maintaining high angular resolution.

Automated Quantitative Multiphase Analysis Using a Focusing Transmission Diffractometer in Conjunction With a Curved Position Sensitive Detector

The method for quantitative X-ray diffraction analysis of multiphase mixtures presented here is based on transmission measurements of thin samples. The integral of all reflections of interest are measured with a position sensitive detector at one time while the transmission factor of the sample is measured simultaneously with a scintillation counter. The method has the advantages that only a few (1-5) mg of substance are required, absorption effects due to sample matrix are measured directly and the method is automated. The measurements are made with the STOE/ Nicolet Automatic Focusing X-ray Diffraction system in conjunction with the STOE/Nicolet Curved Position Sensitive Detector.

Rapid Non-Destructive X-Ray Characterization of Solid Fuels/Propellants

AbstractNumerous studies have been conducted into the microstructural origin of the instability and unpredictability of various energetic materials. Some of these materials are RDX/HMX, Ammonium Perchlorate, Aluminum, etc. Many techniques both destructive and non-destructive have so far been utilized in an attempt to quatify the energetic properties of their composites. These composites may contain one or more energetic constituents in an elastomeric binder. Non-destructive X-ray characterization techniques have been successfully employed to measure several microstructural parameters. Previous studies have shown considerable differences among various production grade RDX. These studies reveal marked differences in the amounts of residual elastic strain and the distribution of dislocations (residual plastic strain) in the constituent RDX phase.The focus of this study is to develop a technique for quantitative constituent phase analysis of solid-propellant (fuel) composites using conventional diffractometry. The use of a Curved Position Sensitive Detector (CPSD) greatly enhances the technique and allows real time applications in production environments. Through the use of computer based Systems and "user friendly" software the required Operator, skill and training have been considerably reduced. The CPSD System has been successfully used to quantify constituent phases (peak heights) and the amounts of residual elastic strain (peak shifts) in these molecular crystal powder mixtures.It is envisioned that rapid, automated, non-destructive X-ray characterization techniques will greatly facilitate production based propellant quality control. A thorough understanding of the relationship between the energetics and microstructural parameters can also he obtained.