Characterizing Atacama B-mode Search Detectors with a Half-Wave Plate

Abstract

The Atacama B-Mode Search (ABS) instrument is a cryogenic ($\sim$10 K) crossed-Dragone telescope located at an elevation of 5190 m in the Atacama Desert in Chile that observed for three seasons between February 2012 and October 2014. ABS observed the Cosmic Microwave Background (CMB) at large angular scales ($40<\ell <500$) to limit the B-mode polarization spectrum around the primordial B-mode peak from inflationary gravity waves at $\ell \sim 100$. The ABS focal plane consists of 480 transition-edge sensor (TES) bolometers. They are coupled to orthogonal polarizations from a planar ortho-mode transducer (OMT) and observe at 145 GHz. ABS employs an ambient-temperature, rapidly rotating half-wave plate (HWP) to mitigate systematic effects and move the signal band away from atmospheric $1/f$ noise, allowing for the recovery of large angular scales. We discuss how the signal at the second harmonic of the HWP rotation frequency can be used for data selection and for monitoring the detector responsivities.

7 pages, 3 figures, conference proceedings submitted to the Journal of Low Temperature Detectors

Cited by in corpus (10)

• Results from the Atacama B-mode Search (ABS) Experiment
• Systematic effects from an ambient-temperature, continuously-rotating half-wave plate
• POLOCALC: a Novel Method to Measure the Absolute Polarization Orientation of the Cosmic Microwave Background
• Calibrating Cluster Number Counts with CMB lensing
• Precipitable water vapour measurement using GNSS data in the Atacama Desert for millimetre and submillimetre astronomical observations
• Development of Calibration Strategies for the Simons Observatory
• Optimal strategy for polarization modulation in the LSPE-SWIPE experiment
• The Simons Observatory: Validation of reconstructed power spectra from simulated filtered maps for the Small Aperture Telescope survey
• The cross correlation of the ABS and ACT maps
• QUIJOTE-TFGI polarization calibration -- Ground characterization and on-sky validation with Tau A and the Moon