The Cosmology Large Angular Scale Surveyor Receiver Design

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.

arXiv commentFixed formatting of abstract; 20 Pages, 11 Figures, SPIE Conference Proceedings

References in corpus (21)

• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Final Maps and Results
• Planck 2013 results. I. Overview of products and scientific results
• The Cosmic Microwave Background Spectrum from the Full COBE/FIRAS Data Set
• Statistics of Cosmic Microwave Background Polarization
• Signature of Gravity Waves in Polarization of the Microwave Background
• The Atacama Cosmology Telescope: The Receiver and Instrumentation
• CLASS: The Cosmology Large Angular Scale Surveyor
• Detectability of Inflationary Gravitational Waves with Microwave Background Polarization
• The Cosmology Large Angular Scale Surveyor
• Task Force on Cosmic Microwave Background Research
• The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz optical design
• Properties of a Variable-delay Polarization Modulator
• Radio-transparent multi-layer insulation for radiowave receivers
• A Projected Estimate of the Reionization Optical Depth Using the CLASS Experiment's Sample-Variance Limited E-Mode Measurement
• The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters
• Recovery of Large Angular Scale CMB Polarization for Instruments Employing Variable-delay Polarization Modulators
• Measuring the Largest Angular Scale CMB B-mode Polarization with Galactic Foregrounds on a Cut Sky
• Silicon-Based Antenna-Coupled Polarization-Sensitive Millimeter-Wave Bolometer Arrays for Cosmic Microwave Background Instruments
• Design and characterization of the Cosmology Large Angular Scale Surveyor (CLASS) 93 GHz focal plane
• Variable-delay Polarization Modulators for Cryogenic Millimeter-wave Applications
• Fabrication of Feedhorn-Coupled Transition Edge Sensor Arrays for Measurement of the Cosmic Microwave Background Polarization

Cited by in corpus (12)

• Four-year Cosmology Large Angular Scale Surveyor (CLASS) Observations: On-sky Receiver Performance at 40, 90, 150, and 220 GHz Frequency Bands
• Two-year Cosmology Large Angular Scale Surveyor (CLASS) Observations: 40 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance
• On-sky performance of the CLASS Q-band telescope
• The Simons Observatory: Metamaterial Microwave Absorber (MMA) and its Cryogenic Applications
• Transition Edge Sensors: Physics and Applications
• Design and characterization of the Cosmology Large Angular Scale Surveyor (CLASS) 93 GHz focal plane
• Modular Inflation at Higher Level $N$
• Large and small field inflation from hyperbolic sigma models
• Cosmology Large Angular Scale Surveyor (CLASS): 90 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance
• Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave background
• High-Efficiency and Low-Noise Detectors for the Upgraded CLASS 90 GHz Focal Plane
• Simons Observatory: Broadband Metamaterial Anti-Reflection Cuttings for Large Aperture Alumina Optics