GLASS AND SILICON FOILS FOR X-RAY SPACE TELESCOPE MIRRORS

摘要

Unique observations delivered by space X-ray imaging telescopes have been significantly contributing to importantdiscoveries of current astrophysics. The telescopes’ most crucial part is a high throughput, heavily nested mirror arrayreflecting X-rays and focusing them to a detector. Future astronomical projects on large X-ray telescopes require novelmaterials and technologies for the construction of the reflecting mirrors. The future mirrors must be lightweight and preciselyshaped to achieve large collecting area with high angular resolution of a few arc sec. The new materials and technologiesmust be cost-effective as well. Currently, the most promising materials are glass or silicon foils which are commerciallyproduced on a large scale. A thermal forming process was used for the precise shaping of these foils. The forced and freeslumping of the foils was studied in the temperature range of hot plastic deformation and the shapes obtained by the differentslumping processes were compared. The shapes and the surface quality of the foils were measured by a Taylor Hobson contactprofilemeter, a ZYGO interferometer and Atomic Forced Microscopy. In the experiments, both heat-treatment temperatureand time were varied following our experiment design. The obtained data and relations can be used for modelling andoptimizing the thermal forming procedure.