The CLASS 150/220 GHz Polarimeter Array: Design, Assembly, and Characterization

Abstract

We report on the development of a polarization-sensitive dichroic (150/220 GHz) detector array for the Cosmology Large Angular Scale Surveyor (CLASS) delivered to the telescope site in June 2019. In concert with existing 40 and 90 GHz telescopes, the 150/220 GHz telescope will make observations of the cosmic microwave background over large angular scales aimed at measuring the primordial B-mode signal, the optical depth to reionization, and other fundamental physics and cosmology. The 150/220 GHz focal plane array consists of three detector modules with 1020 transition edge sensor (TES) bolometers in total. Each dual-polarization pixel on the focal plane contains four bolometers to measure the two linear polarization states at 150 and 220 GHz. Light is coupled through a planar orthomode transducer (OMT) fed by a smooth-walled feedhorn array made from an aluminum-silicon alloy (CE7). In this work, we discuss the design, assembly, and in-lab characterization of the 150/220 GHz detector array. The detectors are photon-noise limited, and we estimate the total array noise-equivalent power (NEP) to be 2.5 and 4 aW$\sqrt{\mathrm{s}}$ for 150 and 220 GHz arrays, respectively.

8 pages, 5 figures, Published in J Low Temp Phys

References in corpus (6)

• CLASS: The Cosmology Large Angular Scale Surveyor
• Advanced code-division multiplexers for superconducting detector arrays
• Precision control of thermal transport in cryogenic single-crystal silicon devices
• On-sky performance of the CLASS Q-band telescope
• 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

Cited by in corpus (23)

• Measuring the spectrum of primordial gravitational waves with CMB, PTA and Laser Interferometers
• QUBIC I: Overview and ScienceProgram
• Four-year Cosmology Large Angular Scale Surveyor (CLASS) Observations: On-sky Receiver Performance at 40, 90, 150, and 220 GHz Frequency Bands
• Beating the Lyth bound by parametric resonance during inflation
• Calibration of Transition-edge Sensor (TES) Bolometer Arrays with Application to CLASS
• QUBIC II: Spectro-Polarimetry with Bolometric Interferometry
• Efficient ILC analysis on polarization maps after EB leakage correction
• Demonstration of 220/280 GHz Multichroic Feedhorn-Coupled TES Polarimeter
• Constraints on the Optical Depth to Reionization from Balloon-Borne CMB Measurements
• Dark Twilight Joined with the Light of Dawn to Unveil the Reionization History
• Cosmology Large Angular Scale Surveyor (CLASS): 90 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance
• Venus Observations at 40 and 90 GHz with CLASS
• Evaluation of the single-component thermal dust emission model in CMB experiments
• Photon noise correlations in millimeter-wave telescopes
• Control and systems software for the Cosmology Large Angular Scale Surveyor (CLASS)
• On-sky performance of new 90 GHz detectors for the Cosmology Large Angular Scale Surveyor (CLASS)
• CMB polarization analysis on circular scans
• Microwave Observations of Venus with CLASS
• Material properties of a low contraction and resistivity silicon-aluminum composite for cryogenic detectors
• The Simons Observatory: Design and Measured Performance of a Carbon Fiber Strut for a Cryogenic Truss
• High-Efficiency and Low-Noise Detectors for the Upgraded CLASS 90 GHz Focal Plane
• Implications of scattering for CMB foreground emission modelling
• Impact of particle production during inflation on the CMB detection