Längenstabilität bei Raumtemperatur von Proben der Glaskeramik "Zerodur"

Abstract

Die Glaskeramik ,,Zerodur" ist als ein Werkstoff mit extrem kleinem Warmeausdehnungskoeffizienten entwickelt worden. Die bekannten Materialeigenschaften werden hier durch Angaben uber langzeitige Langenanderungen erganzt. Wahrend einer Beobachtungszeit von 10 Jahren zeigen drei Proben des Materials, die verschiedene thermische Behandlungen erfahren hatten, unterschiedliche Verkurzungen, die sich durch mathematische Formeln (logarithmisch, hyperbolisch, exponentiell) fast gleich gut beschreiben lassen. Die relativen Langenanderungen pro Jahr liegen zwischen -0.69 . a-' und -0,03 . a-'.

A Versatile Technique to Enable Sub-Milli-Kelvin Instrument Stability for Precise Radial Velocity Measurements: Tests With the Habitable-Zone Planet Finder*

“…For a uniform change in temperature DT on the grating, this RV error can be shown to equal, In addition, the groove density of the grating can also change if the echelle substrate material varies in dimension over long timescales. This is a known effect with Zerodur, and has been documented in the literature by Bayer-Helms et al (1985), who looked at the dimensional stability of Zerodur over multiple decades. They characterize the aging of Zerodur with an aging coefficient A,…”

Thermal issues in machine tools

“…Environmental influences like machine shop temperature generally lead to slow changes of machine tool temperatures, but affect the whole volumetric performance. Internal influences like heat generated by bearings and guideways, lead to a local deformation of the machine tool structure and therefore lead to displacements, which change the volumetric performance partially [4,123,124,125,133,134,135,139,168,173,182,196]. Displacements caused by internal heat sources are less predictable and can change faster than those caused by the environment.…”

“…Stressing unit to measure the thermal distortion under load condition (forces are simulated with a hydraulic pump) [17] Machine errors caused by temperature change in time and space can be experimentally determined by temperature invariant reference objects or independent length measurements. Methods and procedures are described in [4,162,203]. New measurement techniques based on multilateration enable the online correction of task-specific machine movements.…”

Ultrahigh long-term dimensional stability of a sapphire cryogenic optical resonator

“…This drift has been extensively studied for glass ceramic cavities. 10,11 Recently Marmet et al 12 used accurate temperature control of an ULE cavity to obtain a linear drift as low as 4.75 kHz͞day. It is of interest to compare the performance of ULE and sapphire cryogenic optical resonators with respect to long-term effects.…”