QUBIC VIII: Optical design and performance
Abstract
The Q and U Bolometric Interferometer for Cosmology (QUBIC) is a ground-based experiment that aims to detect B-mode polarization anisotropies [1] in the CMB at angular scales around the ℓ ≃100 recombination peak. Systematic errors make ground-based observations of B modes at millimetre wavelengths very challenging and QUBIC mitigates these problems in a somewhat complementary way to other existing or planned experiments using the novel technique of bolometric interferometry. This technique takes advantage of the sensitivity of an imager and the systematic error control of an interferometer. A cold reflective optical combiner superimposes the re-emitted beams from 400 aperture feedhorns on two focal planes. A shielding system composed of a fixed groundshield, and a forebaffle that moves with the instrument, limits the impact of local contaminants. The modelling, design, manufacturing and preliminary measurements of the optical components are described in this paper.
- Publication:
-
Journal of Cosmology and Astroparticle Physics
- Pub Date:
- April 2022
- DOI:
- 10.1088/1475-7516/2022/04/041
- arXiv:
- arXiv:2008.10119
- Bibcode:
- 2022JCAP...04..041O
- Keywords:
-
- CMBR detectors;
- CMBR experiments;
- CMBR polarisation;
- gravitational waves and CMBR polarization;
- Astrophysics - Instrumentation and Methods for Astrophysics;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Part of a series of 8 papers on QUBIC to be published in a special issue of JCAP. Accepted for publication