Iuliano, JeffreyEimer, JosephParker, LucasRhoades, GaryHelson, Kyleet al2022-02-082022-02-082018-07-10Jeffrey 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.https://doi.org/10.1117/12.2312954http://hdl.handle.net/11603/24138Authors: Jeffrey Iuliano, Joseph Eimer , Lucas Parker, Gary Rhoades, Aamir Ali, John W. Appel, Charles Bennett , Michael Brewer , Ricardo Bustos , David Chuss , Joseph Cleary , Jullianna Couto, Sumit Dahal, Kevin Denis, Rolando Dünner , Thomas Essinger-Hileman, Pedro Fluxa , Mark Halpern , Kathleen Harrington , Kyle Helson, Gene Hilton , Gary Hinshaw , Johannes Hubmayr , John Karakla , Tobias Marriage , Nathan Miller , Jeffrey John McMahon, Carolina Nuñez, Ivan Padilla , Gonzalo Palma , Matthew Petroff , Bastian Pradenas Márquez, Rodrigo Reeves , Carl Reintsema , Karwan Rostem , Deniz Augusto Nunes Valle, Trevor Van Engelhoven, Bingjie Wang , Qinan Wang , Duncan Watts , Janet Weiland , Edward J. Wollack , Zhilei Xu, Ziang Yan , Lingzhen ZengSPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United StatesThe 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.19 pagesen-USThis 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 1.0http://creativecommons.org/publicdomain/mark/1.0/Text