Papers by Keyword: Monochromator

Abstract: Reflectometry technique in Centre de Recherché Nucléaire de Draria (CRND) is operational since 2002. The instrument is used for investigation of monochromators and supermirrors. In this communication, several monochromators: 10 and 40 nickel-titanium bilayers deposited on a float-glass substrate with different period are analysed. The investigation of magnetic multilayers (25 silicon-iron bilayers monochromator) is also performed. From the results, Bragg peaks were identified indicating the periodicity of the multilayers.

Abstract: Recent progress in engineering includes the development of new materials and innovations in their processing and treatments. Material technologies, like the study of metals, alloys, ceramics and composites, especially non-destructive analyses of residual stresses profiles and textures, have gained an increasing importance. The dedicated residual stress diffractometers E3 and E7 at BENSC, HMI, Berlin are already equipped with new two-dimensional position sensitive detectors. An upgrade of the monochromator system is planned for 2006 which includes perfectly bent silicon crystals in order to optimise both intensity and angular resolution yielding a large gain of the diffractometer efficiency for strain measurements. A range of equipment for sample positioning is available, such as a closed Eulerian cradle for samples with weights of up to 5 kg, a second cradle for heavy samples (up to 50 kg) with the ability to tilt the samples up to 90° and a translation table carrying samples of up to 300 kg and 1000 mm in diameter. Gauge volumes can be adjusted by a new computer controlled variable slitsystem in a range from 1x1x1 mm³ up to several mm³. In-situ residual stress analysis can be performed within industrial components during mechanical or thermal loading (up to 2000 K). Rapid data visualization as well as evaluation is performed by the specially designed software. The powder diffraction pattern is calculated by summation over the scattering angle dependent Debye- Scherrer lines on the two-dimensional 400*400 mm² planar area detector. A large amount of beam time is exclusively used for industrial research. Among the components that were investigated are crankshafts, impellers, pistons, cylinder heads, turbine blades and welds. Both instruments are similarly designed, where E3 is set up for higher flux and therefore penetration depths and E7 is designed for higher angular resolution.

Abstract: The Heusler alloy Cu2MnAl is a ferromagnetic compound that is in the form of a single crystal suitable for the simultaneous monochromatization and polarization of a neutron beam. Our purpose is to produce such a monochromator. Pre-cast polycrystalline samples were resolidified in crucibles made of different materials with different sizes in the Universal Multizone Crystallizator (UMC) developed in the Institute of Material Sicence at University of Miskolc. Single crystals were obtained as a result of the resolidification. The quality of the single crystals was verified with neutron diffraction, then the ones having suitable quality were oriented crystallographically by using the Laue method. By using the spark machining method, seed crystals with suitable orientation were cut from the single crystals, and oriented single crystals will be grown from them.

Abstract: The Heusler alloy is a ferromagnetic compound (Cu2MnAl), that is suitable for the simultaneous monochromatization and polarization of the neutron beam in the form of singlecrystal. The prespecimen were cast in shell-sand or permanent steel moulds, then they were resolidified in crucibles of different size and material in the Universal Multi-zone Crystallizer (UMC) developed in the Institute of Material Sciences of Miskolc University. The solidified samples were investigated by means of a light microscope, electron microscope, energy disperse microprobe, X-ray diffraction as well as neutron scattering experiments.