Feasibility of transmission x-ray microscopy at 4 keV with spatial resolutions below 150 nm

The feasibility of a transmission x-ray microscope operating in the 3-7 keV photon energy range using phase zone plates (ZPs) has been tested. It has been demonstrated that, at a photon energy of 4 keV, structures smaller than 150 nm can be resolved with good contrast using exposure times in the second to minute range. A large diameter gold ZP was used as condenser and a tungsten ZP with an outermost zone width of 128 nm was used as a high spatial resolution imaging objective lens. Images with a field size of 10×10 μm² were acquired using a charge coupled device camera optically coupled to a phosphor screen. The corresponding pixel size in the object plane was 70 nm.