Scanning X-ray interferometry and the silicon lattice parameter: towards relative uncertainty?

Abstract

In order to reduce measurement uncertainty of the (220) lattice spacing of silicon to a few parts per 109, 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.