Abstract
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 the method to a gold zone plate with 70 nm outermost zone width, 160 μm diameter, and 660 nm zone height, the absolute first order efficiency was measured to be 8.7% ± 0.6%, which is 73% of the theoretically calculated value.