The Atacama B-mode Search: an experiment to measure the polarization of the cosmic microwave background at large angular scales
نویسندگان
چکیده
The Atacama B-mode Seach (ABS) is a new experiment to probe the inflationary epoch in the early universe by measurng the patterns of polarization anisotropy in the cosmic microwave background (CMB) at large angular scales. The polarization of the CMB observed on the celestial sphere can be described with a tensor field. Gravitational waves from inflation, if it occurred, lead to a pseudoscalar component of that tensor field, which is quantified versus angular wavenumber as B-modes [1, 2]. ABS is designed to measure the CMB polarization over a wide frequency band at 145 GHz, using novel detectors optimized for polarization, fabricated at NIST. The detectors are bolometers, based on transition-edge sensors (TES), coupled to feedhorns. ABS features a large focal plane array of detectors illuminated by two ≈ 60 cm mirrors cooled to 4 K. The incoming polarization of the CMB is rotated with a warm half-wave plate (HWP) at the dewar aperture. ABS will make observations at a high-altitude site in the Atacama Desert of Chile.
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