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Proceedings Paper • Open Access

Precision mechanisms for optics in a vacuum cryogenic environment
Author(s): R. Navarro; E. Elswijk; N. Tromp; J. Kragt; G. Kroes; H. Hanenburg; M. de Haan; M. Schuil; M. Teuwen; H. Janssen; L. Venema

Paper Abstract

To achieve superb stability in cryogenic optical systems, NOVA-ASTRON generally designs optical instruments on the basis of a 'no adjustments' philosophy. This means that in principle no corrections are possible after assembly. The alignment precision and consequently the performance of the instrument is guaranteed from the design, the tolerance analysis and the detailed knowledge of the material behavior and manufacturing process. This resulted in a higher degree of integrated optomechanical-cryogenic design with fewer parts, but with a higher part complexity. The 'no adjustments' strategy is successful because in the end the risk on instrument performance and project delays is much reduced. Astronomical instrument specifications have become more challenging over the years. Recent designs of the European Southern Observatory Very Large Telescope Interferometer (ESO VLTI) 4 Telescope combiner MATISSE include hundreds of optical components in a cryogenic environment. Despite the large number of optical components the alignment accuracy and stability requirements are in the order of nanometers. The 'no adjustments' philosophy would be too costly in this case, because all components would need to meet extremely tight manufacturing specifications. These specifications can be relaxed dramatically if cryogenic mechanisms are used for alignment. Several mechanisms have been developed: a tip-tilt mirror mechanism, an optical path distance mechanism, a slider mechanism, a bistable cryogenic shutter and a mirror mounting clip. Key aspects of these mechanisms are that the optical element and mechanism are combined in a compact single component, driven by e.g. self braking piezo actuators in order to hold position without power. The design, realization and test results of several mechanisms are presented in this paper.

Paper Details

Date Published: 20 November 2017
PDF: 7 pages
Proc. SPIE 10565, International Conference on Space Optics — ICSO 2010, 105651S (20 November 2017); doi: 10.1117/12.2309124
Show Author Affiliations
R. Navarro, NOVA-ASTRON (Netherlands)
E. Elswijk, NOVA-ASTRON (Netherlands)
N. Tromp, NOVA-ASTRON (Netherlands)
J. Kragt, NOVA-ASTRON (Netherlands)
G. Kroes, NOVA-ASTRON (Netherlands)
H. Hanenburg, NOVA-ASTRON (Netherlands)
M. de Haan, NOVA-ASTRON (Netherlands)
M. Schuil, NOVA-ASTRON (Netherlands)
M. Teuwen, JPE (Netherlands)
H. Janssen, JPE (Netherlands)
L. Venema, ASTRON (Netherlands)

Published in SPIE Proceedings Vol. 10565:
International Conference on Space Optics — ICSO 2010
Errico Armandillo; Bruno Cugny; Nikos Karafolas, Editor(s)

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