Mechanical design of a UHV non-magnetic kappa diffractometer

A UHV non-magnetic kappa geometry diffractometer has been designed for the resonant soft X-ray scattering (RSXS) branch of the Intermediate Energy X-ray (IEX) beamline at the Advanced Photon Source (APS), Argonne National Laboratory. The kappa geometry allows for a large q-range and space for a sample environment (electric or magnetic fields). To avoid distorting the sample environment field, non-magnetic SmarAct, GmbH stages are used for the ϕ-axis, X, Y, and Z linear stages. The κ and θ axes are controlled by high-precision UHV compatible Physik Instrumente (PI) GmbH & Co. rotation stages. The design goal was to achieve a 50 µm sphere of confusion. To achieve this, iterative designs were developed using FEA and commercial stages were chosen that had minimal wobble, eccentricity, and flatness errors.