Design and development of a practical x-ray interferometers for length metrology

Advanced manufacturing exploiting nanotechnology requires sub nanometre accuracy for length metrology. The Consultative Committee for Length's Nano Working Group proposal to adopt the silicon lattice parameter as an alternative SI metre realisation for nanometrology has been accepted and this will be incorporated into the Mise en Pratique for the metre in 2019.

The use of the silicon lattice parameter can be realised via x-ray interferometry (XRI): used either as ruler or nanopositioning device with a 200 pm period (c.f 158000 pm for optical interferometry).

By exploiting recent advances in key technologies of silicon machining, we will design & build the next generation of XRIs in the UK with the aim of commercial exploitation. The proposed instruments will provide traceable performance verification and calibration for a wide range of novel displacement sensors and actuators working the nm and sub-nm level and lead to a new product range for NPL Instruments.

3) Key research objectives

3.1 Modelling of precise flexure devices

3.2 Efficient production process of monolithic x-ray interferometers for a range of applications

3.3 Designs suitable for sensor characterization and nanopositioning

4) Project plan and deliverables

Year 1:
4.1 Introduction and induction at NPL
4.2 Training with attendance of CDT lectures at NPL
4.3 Literature review of x-ray interferometer, flexures and precision machining
4.4 Design of flexures,
4.5 Set up of x-ray facility for alignment of silicon
4.6 Set up of x-ray topography facility
4.7 Production of fixed lamella XRI

Year 2: Design of flexures and initial x-ray interferometers with flexures

Year 3: Optimisation of design
Year 4: Production of x-ray interferometers and demonstration of their performance