The thermal design, characterization, and performance of the Spider long-duration balloon cryostat
Department of Physics, Princeton University, Princeton, NJ, United States; School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom; Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada; Department of Physics, University of Toronto, Toronto, ON, Canada; Department of Physics, Case Western Reserve University, Cleveland, OH, United States; Jet Propulsion Laboratory, Pasadena, CA, United States; Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA, United States; Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON, Canada; Theoretical Physics, Blackett Laboratory, Imperial College, London, United Kingdom; National Institute of Standards and Technology, Boulder, CO, United States; Department of Physics, Stanford University, Stanford, CA, United States; Kavli Institute for Cosmology, University of Cambridge, Cambridge, United Kingdom; Arizona State University, Tempe, AZ, United States; School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa; Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON, Canada; Department of Physics, University of Illinois at Urbana-ChampaignIL, United States; Department of Astrophysical Sciences, Princeton University, Princeton, NJ, United States; Institut d'Astrophysique Spatiale, Orsay, France; Canadian Institute for Advanced Research CIFAR Program in Cosmology and Gravity, Toronto, ON, Canada
We describe the Spider flight cryostat, which is designed to cool six millimeter-wavelength telescopes during an Antarctic long-duration balloon flight. The cryostat, one of the largest to have flown on a stratospheric payload, uses liquid 4He to deliver cooling power to stages at 4.2 and 1.6 K. Stainless steel capillaries facilitate a high flow impedance connection between the main liquid helium tank and a smaller superfluid tank, allowing the latter to operate at 1.6 K as long as there is liquid in the 4.2 K main tank. Each telescope houses a closed cycle 3He adsorption refrigerator that further cools the focal planes down to 300 mK. Liquid helium vapor from the main tank is routed through heat exchangers that cool radiation shields, providing negative thermal feedback. The system performed successfully during a 17 day flight in the 2014-2015 Antarctic summer. The cryostat had a total hold time of 16.8 days, with 15.9 days occurring during flight. © 2015 Elsevier Ltd. All rights reserved.
Balloons; Cosmology; Cryostats; Heating; Helium; Liquefied gases; Liquids; Meteorological balloons; Sounding rockets; Stainless steel; Tanks (containers); Telescopes; Adsorption refrigerator; Cosmic microwave backgrounds; Instrumentation; Long duration balloons; Millimeter wavelength; Stratospheric payload; Thermal designs; Thermal feedback; Superfluid helium