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arXiv · 2105.08734

Superfluid Liquid Helium Control for the Primordial Inflation Polarization Explorer Balloon Payload

A. Kogut·T. Essinger-Hileman·D. Fixsen·L. Lowe·P. Mirel·E. Switzer·E. Wollack
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Abstract

The Primordial Inflation Polarization Explorer (PIPER) is a stratospheric balloon payload to measure polarization of the cosmic microwave background. Twin telescopes mounted within an open-aperture bucket dewar couple the sky to bolometric detector arrays. We reduce detector loading and photon noise by cooling the entire optical chain to 1.7 K or colder. A set of fountain-effect pumps sprays superfluid liquid helium onto each optical surface, producing helium flows of 50--100 cm^3 / s at heights up to 200 cm above the liquid level. We describe the fountain-effect pumps and the cryogenic performance of the PIPER payload during two flights in 2017 and 2019.

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A. Kogut, T. Essinger-Hileman, D. Fixsen, L. Lowe, P. Mirel, E. Switzer, E. Wollack. 2021-05-18. Superfluid Liquid Helium Control for the Primordial Inflation Polarization Explorer Balloon Payload. https://doi.org/10.1063/5.0048800

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