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1 July 1990 ULE channeled mirror fabrication
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ULETM, a zero expansion glass, offers many advantages as mirror blank material due to its thermal and mechanical properties as well as the flexibility it offers in design and fabrication. Produced by the flame hydrolysis process, this titanium silicate has high homogeneity of Coefficient of Thermal Expansion (CTE) that can be determined within any piece of ULE by nondestructive ultrasonic measurements. The ability to fusion-seal the glass while maintaining strength offers mirror manufacturing design freedom. Coming has produced a 12 inch square plano blank and a 24 inch diameter meniscus, both fabricated with cooling channels, using existing fusion techniques. The square blank was manufactured by actually machining grooves into the plates prior to fusing them together. The meniscus production consisted of fusing bars of ULE between the two outside plates. The meniscus was subsequently thermally tested by NOAO. A 4 meter solid monolithic meniscus with cooling channels is an extension of this fusion technology.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Julie Spangenberg-Jolley, Thomas W. Hobbs, and Gary Proulx "ULE channeled mirror fabrication", Proc. SPIE 1236, Advanced Technology Optical Telescopes IV, (1 July 1990);

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