Optically polished surfaces parallel to the (220) lattice planes of silicon monocrystals

Abstract

An apparatus whereby silicon monocrystals, such as those used in x-ray optics, can be cut and optically polished accurately parallel to known lattice planes is described. A parallelism to within 10 µrad has been obtained.

A More Accurate Measurement of the 28Si Lattice Parameter

“…The two (front and rear) analyser mirrors are polished parallel to the {220} planes. The residual misalignments, |n − h| = 13.7(1.2) µrad and |n −ĥ| = 10.8(1.2) µrad for the front and rear mirrors, with reference to the obverse layout of the analyser, were estimated by a least-squares adjustment of the misalignment between x-ray and light reflections on the mirrors and lattice planes, 27 the phase shift of the x-ray fringes when the analyser motion lies in the mirror planes, and the measured angle between the two mirrors. In order to calculate the relevant correction and the associated uncertainty, the angle between the trihedron and analyser was periodically measured to within a 10 µrad uncertainty; examples of the measurement results are shown in Fig.…”

Measurement repetitions of the Si(220) lattice spacing

“…Consequently, the raw d 220 value was corrected by αβ, where α is the angle between the (220) planes and the front mirror and β is the bisection error. The measurement of the parallelism error between the analyser front-mirror and (220) planes is described in [20]. The results are α z = (−15 ± 10) µrad (vertical direction) and α y = (−160 ± 10) µrad (horizontal direction).…”

Defocused travelling-fringes in scanning triple-Laue x-ray interferometry

“…For the experimental verification of the these predictions, we mined useful data from the archive of the lattice parameter measurements carried out in 2010. At that time, to countercheck a previous measurement of the angle between the analyser front mirror and the diffracting planes [24,25], we defocused the interferometer by moving the analyser transversally, in a direction opposite the z axis in Fig. 2, and archived the interferometer signals before and after the displacement.…”