Reference : ION BEAM FIGURING OF CVD SILICON CARBIDE MIRRORS
Scientific congresses and symposiums : Paper published in a book
Engineering, computing & technology : Aerospace & aeronautics engineering
http://hdl.handle.net/2268/74713
ION BEAM FIGURING OF CVD SILICON CARBIDE MIRRORS
English
Gailly, Patrick mailto [Université de Liège - ULg > > CSL (Centre Spatial de Liège) >]
Mar-2004
Proceedings of the 5th International Conference on Space Optics (ICSO 2004)
Warmbein, B
ESA Publications Division
691-697
No
International
92-9092-865-4
Noordwijk
The Netherlands
5ième Conférence Internationale d’Optique Spatiale (ICSO 2004)
from 30-03-2004 to 2-4-2004
ESA
Toulouse
France
[en] ion beam figuring ; silicon carbide ; space optics
[en] Optical and structural elements made of silicon carbide are increasingly found in space instruments. Chemical vapor deposited silicon carbide (CVD-SiC) is used as a reflective coating on SiC optics in reason of its good behavior under polishing. The advantage of applying ion beam figuring (IBF) to CVD-SiC over other surface figure-improving techniques is discussed herein. The results of an IBF sequence performed at the Centre Spatial de Liège on a 100 mm CVD-SiC mirror are reported. The process allowed to reduce the mirror surface errors from 243 nm to 13 nm rms . Beside the surface figure, roughness is another critical feature to consider in order to preserve the optical quality of CVD-SiC . Thus, experiments focusing on the evolution of roughness were performed in various ion beam etching conditions. The roughness of samples etched at different depths down to 3 m was determined with an optical profilometer. These measurements emphasize the importance of selecting the right combination of gas and beam energy to keep roughness at a low level. Kaufman-type ion sources are generally used to perform IBF but the performance of an end-Hall ion source in figuring CVD-SiC mirrors was also evaluated in this study. In order to do so, ion beam etching profiles obtained with the end-Hall source on CVD-SiC were measured and used as a basis for IBF simulations.
Région wallonne : Direction générale des Technologies, de la Recherche et de l'Energie - DGTRE
Usinage ionique
Researchers ; Professionals ; Students ; General public
http://hdl.handle.net/2268/74713

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Restricted access
paper pgailly icso2004.pdfAuthor postprint394.9 kBRequest copy

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.