X-ray interferometer calibration of microdisplacement transducers

A Rank-Taylor-Hobson-Talystep transducer has been coupled to an X-ray interferometer in order to assess the possibility of calibration of very high-resolution transducers down to sub-nm displacements, using an X-ray interferometer, which has approximately 10 pm resolution traceable to absolute length standards to 1 in 10 6 . It is demonstrated that the two instruments can be simultaneously operated at their full precision, and that absolute metrological measurement down to 10 pm should be feasible. The mounting of the available X-ray interferometer introduced parasitic deflections in this application, which were fully evaluated. A design is proposed for a metrological X-ray interferometer that eliminates these errors and also provides a quadrature output for sensing the direction of displacement.