NanoXAS, a novel concept for high resolution microscopy

Abstract

We currently develop a novel type of scanning x-ray microscope. This instrument will combine the chemical specificity of x-ray absorption spectroscopy with the very high spatial resolution of scanning probe microscopy . In a fundamentally new instrumental approach, the instrument can be used as a conventional scanning transmission x-ray microscope (STXM), as a conventional scanning probe microscope (SPM) or in a mode combining these two techniques. In the latter case, the sample is placed in the focus generated by the fresnel zone plate of the STXM. The SPM-tip placed downstream acts as as a local detector of the emitted photoelectrons. Simulations and experiments have shown that the use of shielded SPM-tips is crucial to obtain a strongly increased chemical resolution. In contrast to similar projects underway at other synchrotrons we use a coaxial geometry. This should greatly enhance the flux density and reduce background signals caused by straylight illuminating the tip.