This paper presents the specifications, design, construction and evaluation of a piezo-driven tip/tilt/focus mechanism which can align a detector or any other optical component in a cryogenic environment. Even with a no-adjustment design philosophy, usually one or two components have to be adjusted in order to compensate for the total of optical and mechanical tolerances in an optical cryogenic instrument. Normally these adjustments are made by means of shims or stiff screw mechanisms and are applied at room temperature. In order to adjust the particular component(s), mostly by just a few microns, the high-risk and time-consuming operation of opening a cryostat is required. For a large cryostat the typical cycle of cooling, testing, warm-up, opening, adjustment, closing and cooling again, takes roughly two weeks. Often the cycle needs to be repeated a few times before the required position is obtained. ASTRON developed a piezo driven tip/tilt/focus mechanism which can adjust a detector or any other optical component in both the ambient and cryogenic (<100 K, vacuum) environment. Only during adjustment the system is active, for the rest of time it is a passive robust system with a high stability. The main specifications are a stroke of ± 0,6 mm and tip/tilt of ±1,2 mrad.

Date Published: 23 July 2008
PDF: 12 pages
Proc. SPIE 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 70184N (23 July 2008); doi: 10.1117/12.788396

Published in SPIE Proceedings Vol. 7018:
Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)