An absolute efficiency measurement technique for Fresnel zone plates using an electron impact micro-focus laboratory
X-ray source (Lα line of Tungsten at 8.4 KeV) is demonstrated. A quasi-monochromatic x-ray image of a zone plate was
obtained employing a pair of copper and cobalt filters. Applying this method to zone plates optimizes the zone plate
fabrication process and provides the ability to explore zone geometry to achieve the best possible efficiency. Several
zone plate parameters were tested with first order efficiency measuring from 1% to 29%.
We have demonstrated dark-field imaging using a full-field hard x-ray microscope by using a custom capillary-based condenser. The condenser provides illumination with a numeric aperture about 3-mrad with high efficiency. This high illumination angle allows full-resolution imaging using a 50 nm hard x-ray zone plate. The zeroth order beam from the condenser is well out of the zoneplate range - which allows a high signal-to-noise ratio in the image plane. Small particles with high scattering power, such as colloidal gold markers used in biology are well-suited for dark-field imaging. Combining with high brightness source from NSRRC BL01B, the dark field image can be acquired within several minutes with high contrast ratio. In this paper, the dark field image of IC and the zoneplate defect will be demonstrated and studied in different energy under dark field mode.
The spatial resolution is a key optical parameter characterizing the performance of an imaging microscope. Zone plate based x-ray microscopy offers the highest spatial resolution over the whole electromagnet wave spectrum. Sub-20 nm resolution have been demonstrated with soft x-rays and sub-60 nm resolution have been obtained with multikeV x-rays using a laboratory source. There are two simple pathways to achieve sub-10 nm resolution x-ray imaging: (1) improving the fabrication technology to produce zone plates with an outermost zone width less than 10 nm and (2) using a higher diffraction order (such as the third diffraction order) of a currently available zone plate.