Design of Cryo-mechanisms for Infrared Astronomy

The Laboratoire d’Astrophysique Experimentale (LAE) at the Universite de Montreal has designed and built several near-infrared cameras/spectrometers in the last decade for the Observatoire du Mont-Megantic (OMM), the Canada-France-Hawaii Telescope (CFHT) and the Herzberg Institute of Astrophysics (HIA). These instruments have required innovative solutions for cryogenic electro-mechanical controls. This paper presents cryogenic motors, bearings, gears, epoxies and positioning/sensing devices at the heart of these cryo-mechanisms. In particular, the paper will focus on a new ball plunger with integrated Hall effect sensor, which can be used both as a mechanical detent and analog position encoder.