The first light of a single-stage MEMS x-ray optic

The first light of a ultra-lightweight and low-cost micro-pore X-ray optic utilizing MEMS (Micro Electro Mechanical Systems) technologies is reported. Our idea is to use silicon (111) planes appeared after anisotropic wet etching of silicon wafers. As a first step to Wolter type-1 optics, a single-stage optic with a focal length of 750 mm and a diameter of 100 mm was designed for energies below 2 keV. The optic consists of 218 mirror chips for X-ray reflection and an optic mount for packing these chips. Design parameters and required fabrication accuracies were determined with numerical simulations. The fabricated optic satisfied these accuracies and its imaging quality was measured at the ISAS X-ray beam line at Al K α 1.49 keV. A focused image was successfully obtained. The measured image size of ~4 mm was consistent with the chip sizes. The estimated X-ray reflectivity also could be explained by micro-roughness of less than 3 nm and geometrical occulting effect due to large obstacle structures on the reflection surface.