The POLARBEAR Experiment

TL;DR

The POLARBEAR experiment is designed to measure the polarization of the cosmic microwave background with high sensitivity, aiming to detect B-mode signals from gravitational lensing and inflationary gravitational waves.

Contribution

This paper introduces the design, characterization, and deployment of the POLARBEAR experiment, a novel high-sensitivity CMB polarization measurement instrument.

Findings

Successful deployment and initial characterization in Chile

High sensitivity to small-scale B-mode signals

Effective control of systematic errors

Abstract

We present the design and characterization of the POLARBEAR experiment. POLARBEAR will measure the polarization of the cosmic microwave background (CMB) on angular scales ranging from the experiment's 3.5 arcminute beam size to several degrees. The experiment utilizes a unique focal plane of 1,274 antenna-coupled, polarization sensitive TES bolometers cooled to 250 milliKelvin. Employing this focal plane along with stringent control over systematic errors, POLARBEAR has the sensitivity to detect the expected small scale B-mode signal due to gravitational lensing and search for the large scale B-mode signal from inflationary gravitational waves. POLARBEAR was assembled for an engineering run in the Inyo Mountains of California in 2010 and was deployed in late 2011 to the Atacama Desert in Chile. An overview of the instrument is presented along with characterization results from observations in Chile.