Sorption-based vibration-free cooler for the METIS instrument on E-ELT

Hermanus J.M. ter Brake, Roger Wu, D.R. Zalewski, Cristian Hendrik Vermeer, Herman J. Holland, J. Doornink, B. Benthem, E. Boom

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

6 Citations (Scopus)
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METIS is the 'Mid-infrared ELT Imager and Spectrograph' for the European Extremely Large Telescope. This E-ELT instrument will cover the thermal/mid-infrared wavelength range from 3 to 14 μm and will require cryogenic cooling of detectors and optics. We present a vibration-free cooling technology for this instrument based on sorption coolers developed at the University of Twente in collaboration with Dutch Space. In the baseline design, the instrument has four temperature levels: N-band: detector at 8 K and optics at 25 K; L/M-band: detector at 40K and optics at 77 K. The latter temperature is established by a liquid nitrogen supply with adequate cooling power. The cooling powers required at the lower three levels are 0.4 W, 1.1 W, and 1.4 W, respectively. The cryogenic cooling technology that we propose uses a compressor based on the cyclic adsorption and desorption of a working gas on a sorber material such as activated carbon. Under desorption, a high pressure can be established. When expanding the high-pressure fluid over a flow restriction, cooling is obtained. The big advantage of this cooling technology is that, apart from passive valves, it contains no moving parts and, therefore, generates no vibrations. This, obviously, is highly attractive in sensitive, high-performance optical systems. A further advantage is the high temperature stability down to the mK level. In a Dutch national research program we aim to develop a cooler demonstrator for METIS. In the paper we will describe our cooler technology and discuss the developments towards the METIS cooler demonstrator
Original languageEnglish
Title of host publicationGround-based and Airborne Instrumentation for Astronomy IV
Subtitle of host publication1–6 July 2012, Amsterdam, Netherlands
EditorsI.S. McLean, S.K. Ramsay, H. Takam
Place of PublicationAmsterdam
ISBN (Print)9780819491473
Publication statusPublished - 1 Jul 2012
EventSPIE Astronomical Telescopes + Instrumentation 2012 - Amsterdam, Netherlands
Duration: 1 Jul 20126 Jul 2012

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X


ConferenceSPIE Astronomical Telescopes + Instrumentation 2012


  • METIS-289400
  • IR-82269


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