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Proceedings Paper

Review of measurement systems for evaluating thermal expansion homogeneity of Corning Code 7971 ULETM
Author(s): Henry E. Hagy
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Paper Abstract

Early on in the development of glass Code 7971 ULETM, Corning recognized that applications demanded thermal expansion measurements with higher precision and accuracy than that available. Hence a program was launched starting with 10cm path laser Fizeau interferometry to establish an absolute base. Differential methods followed with large sandwich seals and a high precision vitreous silica superdilatometer. Destructive in nature, these tests led to a nondestructive ultrasonic procedure that permits absolute and differential measurements with an uncertainty of +/- 2 ppb/ degree(s)C and reliably performed at the manufacturing plant. Details of these measurement systems are described along with optional experimental variations. A principle, established with seal testing, is reviewed showing that expansion differentials in ULETM are independent of temperature. Finally, recent plant measurements of both axial and radial thermal expansion variations in ULETM boules are presented.

Paper Details

Date Published: 1 December 1991
PDF: 14 pages
Proc. SPIE 1533, Optomechanics and Dimensional Stability, (1 December 1991); doi: 10.1117/12.48856
Show Author Affiliations
Henry E. Hagy, Corning Incorporated Consultant (United States)

Published in SPIE Proceedings Vol. 1533:
Optomechanics and Dimensional Stability
Roger A. Paquin; Daniel Vukobratovich, Editor(s)

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