Investigation of phase contrast hard X-ray microscopy using planar sets of refractive crossed linear parabolic lenses made from SU-8 polymer

Planar X-ray refractive lenses with parabolic surface profile, and in crossed geometry to provide 2D focusing, are fabricated from SU-8 polymer using the LIGA process and deep X-ray lithography technology. A transmission X-ray microscope (TXM) using a condenser and an objective lens based on this type of X-ray optics was set up at the ESRF beamline BM 5, for photon energies of 17.1 and 18 keV. Test structures made of gold and SU-8, with different thicknesses, were imaged with this TXM using in-line phase-contrast, with X-ray magnification factors of 13-20, spatial resolution between 0.2 and 0.3 μm and exposure times around 1 s. The advantages of a TXM based on refractive SU-8 planar crossed condenser and objective and the optimisation of the optical scheme and of the condenser focusing profile are discussed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)