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See detailRoughness evolution of some X-UV reflective materials induced by low energy (< 1 keV) ion beam milling
Gailly, Patrick ULg; Jamar, Claude ULg; Fleury-Frenette, Karl ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2004), 216

Ion beam figuring (IBF) is an advanced technique that is been used for more than 10 years as a final step in the manufacturing of optical elements. It makes use of ion sputtering to correct shape defects ... [more ▼]

Ion beam figuring (IBF) is an advanced technique that is been used for more than 10 years as a final step in the manufacturing of optical elements. It makes use of ion sputtering to correct shape defects but this process may eventually lead to the degradation of the surface roughness. In this study, the evolution of roughness for some optical materials subjected to the ion beam figuring process has been investigated by using optical profilometry and scanning electron microscopy. Emphasis has been made on electroplated nickel, PVD gold and CVD silicon carbide. These materials are often used for X-ray and UV applications but only limited data on their behavior under ion milling is currently available. Roughness measurements have been performed at different etching depths down to 5 mum which is representative of typical IBF treatments. The effects of using different inert gases (Ar, Kr and Xe) with ion energies ranging from 200 to 900 eV have been studied. The observed trends are an important increase of the roughness for electroplated nickel, a slight decrease for PVD gold and a slight increase for CVD silicon carbide. Results are discussed in relation to previous related works and within sputtering considerations. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailDevelopment of a metrology and figuring machine for large X-ray mirror
Gailly, Patrick ULg; de Chambure, Daniel; Collette, Jean Paul et al

Conference (2003, February 20)

To improve the image quality of X-ray replicated mirror, A new metrology machine has been built link to a ion beam figuring machine. The first one allows to accurately measure the shape of replicated X ... [more ▼]

To improve the image quality of X-ray replicated mirror, A new metrology machine has been built link to a ion beam figuring machine. The first one allows to accurately measure the shape of replicated X-ray mirrors. The machine is dedicated to cylindrical mirrors shape whose dimensions can vary from 50 to 800 mm in height and 600 to 800 mm in diameter. The present contribution will sum up the results achieved with this machine on an actual mirror. The machine calibration results and the data analysis to obtain the mirror final shape will be detailed. The final results are compared with other measurements performed by a traditional 3-D machine. The second one is a dedicated ion figuring machine dedicated for the figuring of the X-ray mirrors. The preliminary tests were undertaken to evaluate the ion figuring process on Nickel replicated surfaces. Those results were used to improve the design of the figuring machine, a detailed description of that machine follows. The reliability of the ion figuring process is shown through an actual problem. Finally, some leading remarks about the improvements of the ion figuring ion machine and the ion figuring process in general are drawn. [less ▲]

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See detailNew process for X-ray mirror image quality improvement
Gailly, Patrick ULg; de Chambure, Daniel; Collette, Jean-Paul et al

in Freund, Andreas K. (Ed.) X-Ray Mirrors, Crystals, and Multilayers II (Proceedings Volume) (2002, December 24)

A new technique to improve the image quality of Ni replicated X-ray mirror is presented. During the manufacturing of XMM Mirror Module between 1994 to 1999, the classical manufacturing process showed its ... [more ▼]

A new technique to improve the image quality of Ni replicated X-ray mirror is presented. During the manufacturing of XMM Mirror Module between 1994 to 1999, the classical manufacturing process showed its limits. In 1995, the XMM Mirror Module Qualification Model HEW was around 20 arcsec. In 1998, the fifth Flight Model Mirror Module reached 11 arcsec HEW, with a single mirror shell achieving 8 arcsec HEW. The performance of this technology is namely limited by the integration process of the shells. The new technique is based on the following philosophy : • Firstly, an accurate measurement of each mirror shell after integration. A dedicated metrology system has been built and allows a precise metrology of the actual surface. • Secondly, a modification of the mirror shell and of the support to transfer the stress to a non optical active area. • Finally, an ion figuring run to correct the residual shape error of the mirror. The control and evaluation of the process is assured by EUV PSF assessment achieved in the FOCAL X facility developed for XMM. The advantages of this new process are to shape the mirrors in their final hardware configuration and the versality of the process enabling improvement of other kinds of high accuracy mirrors. [less ▲]

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