Micromachined X-ray collector for space astronomy

A novel micromachined X-ray collector using anisotropically etched Si(1 1 1) side walls as X-ray mirrors for future astronomical missions is reported. The collector was designed to converge a ϕ 100 mm parallel X-ray beam into a ϕ 4 mm focus. In order to obtain smooth Si(1 1 1) side walls, dynashock-type ultrasonic waves were added during the anisotropic KOH etching. The surface roughness on the order of nm or less was achieved. The sidewalls or the X-ray mirrors were diced from the wafer as mirror chips and then adhered to a mount formed by deep reactive ion etching. The first light image was successfully obtained at Al Kα 1.49 keV in a ISAS 30 m-long X-ray beam line.