Development of Multilevel-type Multilayer Lens for X-rays

A multilayer (sputtered-sliced) Fresnel zone plate (FZP) is one of promising focusing optics for high-energy X-rays. In order to attain high diffraction efficiency, two types of multilevel-type multilayer FZPs have been fabricated, and these focusing characteristics have been measured at SPring-8. The FZPs composed of concentric multilayers of alternating high-Z(Cu), low-Z(Al), and several types of composite materials layers by Cu and Al. As a result, (1) no significant difference was observed both the measured beam size and the diffraction efficiency of a FZP during 9 months to the FZP with 4-step structure, (2) the diffraction efficiency of the 1st order focus and the focused beam size measured by the knife-edge scanning were more than 50% and 0.8 μm at 41.3 keV, respectively to the FZP with 6-step structure.