Design, fabrication, and characterization of silicon pore optics for ATHENA/IXO

Silicon pore optics is a technology developed to enable future large area X-ray telescopes, such as the International X-ray Observatory (IXO) or the Advanced Telescope for High ENergy Astrophysics (ATHENA), an L-class candidate mission in the ESA Space Science Programme 'Cosmic Visions 2015-2025'. ATHENA/IXO use nested mirrors in Wolter-I configuration to focus grazing incidence X-ray photons on a detector plane.

The x-ray optics will have to meet stringent performance requirements including an effective area of a few m2 at 1.25 keV and angular resolution between 5(IXO) and 9(ATHENA) arc seconds. To achieve the collecting area requires a total polished mirror surface area close to 1000 m2 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 can be met without any costly polishing steps. Two of such 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. In this paper we will present the silicon pore optics mass manufacturing process and latest X-ray test results.