The Cosmology Large Angular Scale Surveyor receiver design
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Author/Creator
Author/Creator ORCID
Date
2018-07-10
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Citation of Original Publication
Jeffrey Iuliano et al. "The Cosmology Large Angular Scale Surveyor receiver design". Proc. SPIE 10708, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 1070828 (10 July 2018) https://doi-org/10.1117/12.2312954.
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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0
Public Domain Mark 1.0
Subjects
Abstract
The Cosmology Large Angular Scale Surveyor consists of four instruments performing a CMB polarization survey.
Currently, the 40 GHz and first 90 GHz instruments are deployed and observing, with the second 90 GHz and a
multichroic 150/220 GHz instrument to follow. The receiver is a central component of each instrument’s design
and functionality. This paper describes the CLASS receiver design, using the first 90 GHz receiver as a primary
reference. Cryogenic cooling and filters maintain a cold, low-noise environment for the detectors. We have
achieved receiver detector temperatures below 50 mK in the 40 GHz instrument for 85% of the initial 1.5 years
of operation, and observed in-band efficiency that is consistent with pre-deployment estimates. At 90 GHz, less
than 26% of in-band power is lost to the filters and lenses in the receiver, allowing for high optical efficiency. We discuss the mounting scheme for the filters and lenses, the alignment of the cold optics and detectors, stray light
control, and magnetic shielding.