On-sky performance of new 90 GHz detectors for the Cosmology Large Angular Scale Surveyor (CLASS)

Date

2023-03-29

Department

Program

Citation of Original Publication

NĆŗƱez, Carolina, John W. Appel, Michael K. Brewer, Sarah Marie Bruno, Rahul Datta, Charles L. Bennett, Ricardo Bustos, et al. ā€œOn-Sky Performance of New 90 GHz Detectors for the Cosmology Large Angular Scale Surveyor (CLASS).ā€ IEEE Transactions on Applied Superconductivity 33, no. 5 (August 2023): 1ā€“4. https://doi.org/10.1109/TASC.2023.3262497.

Rights

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

Subjects

Abstract

The Cosmology Large Angular Scale Surveyor (CLASS) is a polarization-sensitive telescope array located at an altitude of 5,200 m in the Chilean Atacama Desert and designed to measure the polarized Cosmic Microwave Background (CMB) over large angular scales. The CLASS array is currently observing with three telescopes covering four frequency bands: one at 40 GHz (Q); one at 90 GHz (W1); and one dichroic system at 150/220 GHz (HF). During the austral winter of 2022, we upgraded the first 90 GHz telescope (W1) by replacing four of the seven focal plane modules. These new modules contain detector wafers with an updated design, aimed at improving the optical efficiency and detector stability. We present a description of the design changes and measurements of on-sky optical efficiencies derived from observations of Jupiter.