Metrological x-ray interferometry in the micrometre region

Abstract

A `free-standing' microdisplacement calibrator is described which utilizes a previously proposed but untested design of monolithic x-ray interferometer. The monolith is driven by a twist-compensating electromagnetic actuator and a specially designed 1 ppm current source and is held, along with its x-ray source and detectors, within a desk-top-mounted radiation enclosure. It is confirmed that highly traceable displacements resolved to a small fraction of a nanometre can be obtained over a continuous range of at least under conditions typical of a routine metrology room. An overview of the system and its performance is given, but this paper concentrates particularly on the monolith design and on vibration suppression