Absolute efficiency measurement of high-performance zone plates

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%.