The GMT's acquisition guiding and wavefront sensing system NOVEC-7100 cooling system

William Podgorski; Daniel Catropa; Brian McLeod; Stuart McMuldroch; Antonin Bouchez; Oliver McIrwin; David Ashby

doi:10.1117/12.2562335

13 December 2020 The GMT's acquisition guiding and wavefront sensing system NOVEC-7100 cooling system

William Podgorski, Daniel Catropa, Brian McLeod, Stuart McMuldroch, Antonin Bouchez, Oliver McIrwin, David Ashby

Proceedings Volume 11445, Ground-based and Airborne Telescopes VIII; 114452A (2020) https://doi.org/10.1117/12.2562335
Event: SPIE Astronomical Telescopes + Instrumentation, 2020, Online Only

Abstract

The GMT Acquisition Guiding and Wavefront Sensing System (AGWS) is responsible for making the measurements required to keep the optics of the seven-segment GMT coaligned, phased, pointing in the correct direction, and conforming to the correct mirror shape. The AGWS consists of four identical probes that patrol the outer parts of the GMT field of view. Each probe is comprised of two channels, a visible channel for guiding and a J-band dispersed fringe sensor channel used to phase the segmented telescope. The four probes are mounted on the GMT Gregorian Instrument Rotator (GIR) just above the focal plane. A GMT Standard Electronics Cabinet, mounted on the GIR below the probes, houses system electronics. Each probe generates 353 watts and is actively cooled. To preclude the generation of a heat plume, disruptive of telescope seeing, the surface temperatures of the AGWS probes must be held to within ±1 deg C of the GMT enclosure temperature. The AGWS probes are located in a sensitive position on the GMT, just above the Direct Gregorian science instruments. A coolant leak in such a position would be dangerous to these instruments. To mitigate the effects of leaks, we have developed an active cooling system based on NOVEC-7100, an engineered cooling fluid produced by 3M™. The advantage of NOVEC-7100 is that it evaporates rapidly should there be a leak and will not damage sensitive optics or electronics should any liquid reach them. In this paper we describe the AGWS NOVEC-7100 cooling system design and performance.

Conference Presentation

Citation Download Citation

William Podgorski, Daniel Catropa, Brian McLeod, Stuart McMuldroch, Antonin Bouchez, Oliver McIrwin, and David Ashby "The GMT's acquisition guiding and wavefront sensing system NOVEC-7100 cooling system", Proc. SPIE 11445, Ground-based and Airborne Telescopes VIII, 114452A (13 December 2020); https://doi.org/10.1117/12.2562335

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