Combined microscope for scanning X-ray transmission and surface topography

A brief description is given of a scanning transmission X-ray microscope (STXM) for use with synchrotron radiation allowing simultaneous X-ray imaging and imaging of surface topography. Surface topography, appropriate to both conducting and non-conducting samples, is sensed by successive "specimen hopping" i.e. planting of the specimen at and withdrawal from a fixed sharp tip, or stylus, formed by the scanning tip of an atomic force microscope (AFM). First experiments are described with 3 keV photons with zone plate resolution of about 100 nm. Preliminary work is also mentioned to add a collimator to improve spatial resolution (in principle to < 20 nm for 300-500 eV photons), by installing a pierced AFM tip at the zone plate focus. The topographic measurement, currently with specimen thickness resolution of about 10 nm, but potential for approximately 1 nm, and feature-dependent in-specimen plane resolution of about 100 nm as limited by the stylus geometry, is an adjunct to the STXM results, to provide information helpful in the interpretation of the X-ray image. Examples are given for simple specimens of the gains in specimen understanding from simultaneous STXM and hopping contact topographic images. Typical applications areas are radiation damage, and dynamic processes like specimen corrosion.