Calibration of detector time constant with a thermal source for the POLARBEAR-2A CMB polarization experiment

Abstract

The Simons Array (SA) project is a ground-based Cosmic Microwave Background (CMB) polarization experiment. The SA observes the sky using three telescopes, and POLARBEAR-2A (PB-2A) is the receiver system on the first telescope. For the ground-based experiment, atmospheric fluctuation is the primary noise source that could cause polarization leakage. In the PB-2A receiver system, a continuously rotating half-wave plate (HWP) is used to mitigate the polarization leakage. However, due to the rapid modulation of the polarization signal, the uncertainty in the time constant of the detector results in an uncertainty in the polarization angle. For PB-2A, the time constant of each bolometer needs to be calibrated at the sub-millisecond level to avoid introducing bias to the polarization signal. We have developed a new calibrator system that can be used to calibrate the time constants of the detectors. In this study, we present the design of the calibration system and the preliminary results of the time constant calibration for PB-2A.

arXiv commentProceedings of the 15th Asia Pacific Physics Conference (APPC15)

References in corpus (6)

• The POLARBEAR-2 and the Simons Array Experiment
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• Performance of a continuously rotating half-wave plate on the POLARBEAR telescope
• Design and development of an ambient-temperature continuously-rotating achromatic half-wave plate for CMB polarization modulation on the POLARBEAR-2 experiment
• The Simons Observatory: gain, bandpass and polarization-angle calibration requirements for B-mode searches
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