A demonstrator for bolometric interferometry

TL;DR

This paper introduces DIBO, a single-baseline bolometric interferometer demonstrator at 90 GHz, validating the BI concept for precise CMB polarization measurements through laboratory characterization and detailed modeling.

Contribution

It presents the design, construction, and laboratory validation of a bolometric interferometry demonstrator for the first time.

Findings

Successful measurement of interference patterns with a room-temperature detector and a 4 K bolometer.

Validation of the BI concept through detailed modeling and experimental data.

Demonstration of phase shift control and source rotation effects in the interferometer.

Abstract

Bolometric Interferometry (BI) is one of the most promising techniques for precise measurements of the Cosmic Microwave Background polarization. In this paper, we present the results of DIBO (Demonstrateur d'Interferometrie Bolometrique), a single-baseline demonstrator operating at 90 GHz, built to proof the validity of the BI concept applied to a millimeter-wave interferometer. This instrument has been characterized in the laboratory with a detector at room temperature and with a 4 K bolometer. This allowed us to measure interference patterns in a clean way, both (1) rotating the source and (2) varying with time the phase shift among the two interferometer's arms. Detailed modelisation has also been performed and validated with measurements.