SCANNING TRANSMISSION X-RAY MICROSCOPY WITH A SEGMENTED DETECTOR

A segmented silicon detector has been developed for the Stony Brook soft x-ray scanning transmission x-ray microscope. The detector combines good detective quantum efficiency (90% at 520 e' and low noise (5 photons/ channel/ integration at 520 eV) with the ability of having up to 10 independent sensitive regions that are matched to the microscope geometry. In addition to the usual bright field images, differential phase contrast images and dark field images are recorded simultaneously in one scan. A Fourier filtering method has been employed to recover an estimate of the sample absorption and phase shift from the partially coherent images collected on the detector segments. 'A reconstruction of a Germanium test pattern exhibits good agreement between the predictions from the tabulated x-ray optical constants and the experiment.