• Boscolo Marchi, Enrico
• Spiga, Daniele
• Bertoli, Juri
• Mattarello, Valentina
• Kools, Jacques
• Salmaso, Guido
• Garoli, Denis
• Tagliaferri, Giampiero
• Pareschi, Giovanni

Abstract

Depth-graded multilayer structures are widely considered as the preferred technology for the next generation of hard Xray telescopes operating in the spectral range up to several tens of keV. This contrasts to earlier generation telescopes which operated in the 1-10 keV range, and utilized single material reflection layers (e.g. Au). Several future space missions are scheduled to include optics comprising up to hundreds of nested shells with Wolter-I profile. Therefore, the need for an industrial strength (in terms of robustness, reliability and precision) manufacturing process for such multilayers has emerged. In this paper, we will discuss the enabling technologies towards "industrial" Physical Vapor Deposition (PVD) technology we have developed for this precision coating process. More specifically, we will review the results obtained on periodic and a-periodic W/Si multilayers, which have been produced on shells of 600 mm height and 300 mm diameter. Points that will be discussed include: Â. Advanced process control based on in-situ sensors and its effect on repeatability and stability of the process. Â. Ex-situ metrology methods Â. Thickness homogeneity over large areas

Topics

• physical vapor deposition
• strength