TEXS: in-vacuum tender X-ray emission spectrometer with 11 Johansson crystal analyzers.

The design and first results of a large-solid-angle X-ray emission spectrometer that is optimized for energies between 1.5 keV and 5.5 keV are presented. The spectrometer is based on an array of 11 cylindrically bent Johansson crystal analyzers arranged in a non-dispersive Rowland circle geometry. The smallest achievable energy bandwidth is smaller than the core hole lifetime broadening of the absorption edges in this energy range. Energy scanning is achieved using an innovative design, maintaining the Rowland circle conditions for all crystals with only four motor motions. The entire spectrometer is encased in a high-vacuum chamber that allocates a liquid helium cryostat and provides sufficient space for in situ cells and operando catalysis reactors.

Design and development of a controlled pressure/temperature set-up for in situ studies of solid-gas processes and reactions in a synchrotron X-ray powder diffraction station.

A novel set-up has been designed and used for synchrotron radiation X-ray high-resolution powder diffraction (SR-HRPD) in transmission geometry (spinning capillary) for in situ solid-gas reactions and processes in an isobaric and isothermal environment. The pressure and temperature of the sample are controlled from 10(-3) to 1000 mbar and from 80 to 1000 K, respectively. To test the capacities of this novel experimental set-up, structure deformation in the porous material zeolitic imidazole framework (ZIF-8) by gas adsorption at cryogenic temperature has been studied under isothermal and isobaric conditions. Direct structure deformations by the adsorption of Ar and N2 gases have been observed in situ, demonstrating that this set-up is perfectly suitable for direct structural analysis under in operando conditions. The presented results prove the feasibility of this novel experimental station for the characterization in real time of solid-gas reactions and other solid-gas processes by SR-HRPD.

Multi-use high/low-temperature and pressure compatible portable chamber for in situ grazing-incidence X-ray scattering studies.

The multipurpose portable ultra-high-vacuum-compatible chamber described in detail in this article has been designed to carry out grazing-incidence X-ray scattering techniques on the BM25-SpLine CRG beamline at the ESRF. The chamber has a cylindrical form, built on a 360° beryllium double-ended conflate flange (CF) nipple. The main advantage of this chamber design is the wide sample temperature range, which may be varied between 60 and 1000 K. Other advantages of using a cylinder are that the wall thickness is reduced to a minimum value, keeping maximal solid angle accessibility and keeping wall absorption of the incoming X-ray beam constant. The heat exchanger is a customized compact liquid-nitrogen (LN2) continuous-flow cryostat. LN2 is transferred from a storage Dewar through a vacuum-isolated transfer line to the heat exchanger. The sample is mounted on a molybdenum support on the heat exchanger, which is equipped with a BORALECTRIC heater element. The chamber versatility extends to the operating pressure, ranging from ultra-high vacuum (<10(-10) mbar) to high pressure (up to 3 × 10(3) mbar). In addition, it is equipped with several CF ports to allocate auxiliary components such as capillary gas-inlet, viewports, leak valves, ion gun, turbo pump, etc., responding to a large variety of experiment requirements. A movable slits set-up has been foreseen to reduce the background and diffuse scattering produced at the beryllium wall. Diffraction data can be recorded either with a point detector or with a bi-dimensional CCD detector, or both detectors simultaneously. The system has been designed to carry out a multitude of experiments in a large variety of environments. The system feasibility is demonstrated by showing temperature-dependence grazing-incidence X-ray diffraction and conductivity measurements on a 20 nm-thick La0.7Ca0.3MnO3 thin film grown on a SrTiO3(001) substrate.

Reliability of the developmental eye movement test.

PURPOSE: This study evaluated the repeatability of the Developmental Eye Movement Test (DEM) with three consecutive administrations on two separate visits to 181 children between the ages of 6 years and 11 years 11 months. METHODS: Children with visual acuity of ≥ 20/25, normal binocularity, and accommodation were administered three different versions of the DEM test. One to 4 weeks after the first administration of the DEM, the children were tested again using the same order for the three versions of the DEM. Measures of within- and between-session repeatability for the vertical-adjusted time, horizontal-adjusted time, ratio, and error scores were determined. RESULTS: The within-session repeatability for vertical- and horizontal-adjusted time were good to excellent but were poor to good for ratio, and poor to fair for errors. The between-session intraclass correlation coefficients were fair to good for both the vertical and horizontal scores but poor for the ratio and error scores. The repeatability of the pass-fail diagnostic classification within a single session for each subject on test and retest was compared. The percentage of patients who remained in the same classification ranged from 71 to 100% for both vertical and horizontal scores. Wider variability was seen with the ratio and error scores showing between 47 and 100% of the children remaining classified as pass or fail with repeated administrations of the DEM. Such findings would suggest that children in this age range may show improvements in all four test scores without any intervention. CONCLUSIONS: Although the DEM is widely used in optometric practice, the results of this study suggest that clinicians should be cautious about using the DEM test in isolation for reaching a diagnosis or monitoring the effectiveness of treatment for saccadic dysfunction.