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Proceedings Paper

Modeling of the thermal expansion behaviour of ZERODUR at arbitrary temperature profiles
Author(s): Ralf Jedamzik; Thoralf Johansson; Thomas Westerhoff
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Paper Abstract

Modeling of the thermal expansion behavior of ZERODUR® for the site conditions of the upcoming Extremely Large Telescope's (ELT's) allows an optimized material selection to yield the best performing ZERODUR® for the mirror substrates. The thermal expansion of glass ceramics is a function of temperature and a function of time, due to the structural relaxation behavior of the materials. The application temperature range of the upcoming ELT projects varies depending on the possible construction site between -13°C and +27°C. Typical temperature change rates during the night are in the range between 0.1°C/h and 0.3°C/h. Such temperature change rates are much smaller than the typical economic laboratory measurement rate, therefore the material behavior under these conditions can not be measured directly. SCHOTT developed a model approach to describe the structural relaxation behavior of ZERODUR®. With this model it is possible to precisely predict the thermal expansion behavior of the individual ZERODUR® material batches at any application temperature profile T(t). This paper presents results of the modeling and shows ZERODUR® material behavior at typical temperature profiles of different applications.

Paper Details

Date Published: 19 July 2010
PDF: 12 pages
Proc. SPIE 7739, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation, 77390I (19 July 2010); doi: 10.1117/12.855980
Show Author Affiliations
Ralf Jedamzik, SCHOTT AG (Germany)
Thoralf Johansson, SCHOTT AG (Germany)
Thomas Westerhoff, SCHOTT AG (Germany)


Published in SPIE Proceedings Vol. 7739:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)

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