102,113 research outputs found
Scanning X-ray interferometry over a millimeter baseline
No full textA new translation device has been developed at the Istituto di Metrologia ''G. Colonnetti'' (IMGC) to improve the measurement of the (220) lattice spacing in silicon by X-ray/optical interferometry, It is capable of millimeter linear displacement and servo controls ensure picometer and nanoradian resolutions in crystal position and attitude, It has been successfully used to drive a scanning X-ray interferometer over a 2 mm displacement, thus extending by more than one order of magnitude the maximum crystal movement obtained before
Scanning X-ray interferometry and the silicon lattice parameter: towards 10(-9) relative uncertainty?
No full textIn order to reduce measurement uncertainty of the (220) lattice spacing of silicon to a few parts per 10(9), a combined X-ray and optical interferometer capable of millimeter scans is being tested. A new series of measurements confirmed the value obtained with our previous set-up, and the bounds of measurement uncertainty were investigated. The article supplements the analysis of the error budget and provides a safer footing for the monocrystalline silicon lattice parameter value
Lattice parameter and thermal expansion of monocrystalline silicon
No full textWe present experimental results for the lattice parameter and the thermal expansion of a silicon monocrystal at room temperature. In the precision determination of the Avogadro constant, an accurate knowledge of the value of the thermal expansion of silicon monocrystals is necessary so that their unit cell and molar volumes can both be referred to the same temperature. Recent advances in x-ray interferometry have made it possible to reduce the uncertainty of that value by one order of magnitude. (C) 1997 American Institute of Physics
Simulation of monolithic silicon LLL scanning X-ray interferometer
No full textA model of a monolithic silicon LLL scanning X-ray interferometer capable of displacements up to 100 mu m is described. It can be used for the measurement of the (2 (2) over bar 0) lattice plane spacing of silicon in studies concerning the Avogadro constant and for the calibration of linear displacement transducers having sub-nanometer sensitivity
Lattice strain effects in the measurement of the Si lattice parameter by Laue-case double-crystal diffractometry
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Non-Linear Analysis of the Elastic Behaviour of a Translation Device for X-Ray Interferometry
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