Correlative Conventional Scanning and Ptychographic Soft X-ray Microscopy

摘要

Recent plans for x-ray synchrotrons to upgrade to new high brightness lattices have created great excitementabout the potential for coherent x-ray imaging to provide a view of nano-materials with high spatial and temporalresolution. However, with increased x-ray brightness comes the inherent risk of radiation damage and the limitedspeed of current experimental systems. The Advanced Light Source has an extensive program in coherentscanning transmission x-ray microscopy (STXM) and ptychographic imaging with four beamlines covering anenergy range of 200 to 2500 eV. Current instrument development efforts are focused on high-dynamic scanningfor increased speed and the use of fast x-ray pixel detectors for high resolution ptychographic imaging. Our newmicroscope, called Nanosurveyor2, can scan at rates of up to 1 mm per second and has achieved a resolution of3 times the x-ray wavelength. Using this system, we are developing novel scan trajectories and low dose imagingmethods which combine high speed conventional STXM imaging with high resolution ptychography. Principalcomponent analysis is used to extract high statistics spectra from noisy and low-resolution STXM data whichare then used to fit a small number of ptychographic images for high spatial resolution chemical mapping withrelatively low dose. We consider applications in the energy sciences where x-ray exposure has been observed toreduce the oxidation state of relevant compounds.