Silicon pore x-ray optics for IXO

Abstract

Silicon pore optics is a technology developed to enable future large area X-ray telescopes, such as the International X-ray Observatory (IXO), a candidate mission in the ESA Space Science Programme 'Cosmic Visions 2015-2025'. IXO uses nested mirrors in Wolter-I configuration to focus grazing incidence X-ray photons on a detector plane. The IXO optics will have to meet stringent performance requirements including an effective area of >2.5 m 2 at 1.25 keV and >0.65 m 2 at 6 keV and angular resolution better than 5 arc seconds. To achieve the collecting area requires a total polished mirror surface area of ~1300 m 2 with a surface roughness better than 0.5 nm rms. By using commercial high-quality 12 silicon wafers which are diced, structured, wedged, coated, bent and stacked, the stringent performance requirements of IXO can be attained without any costly polishing steps. Two of these stacks are then assembled into a co-aligned mirror module, which is a complete X-ray imaging system. Included in the mirror module are the isostatic mounting points, providing a reliable interface to the telescope. Hundreds of such mirror modules are finally integrated into petals, and mounted onto the spacecraft to form an X-ray optic of approximately 4 m in diameter. In this paper we will present the silicon pore optics mass manufacturing process and latest X-ray test results of mirror modules mounted in flight configuration.