Developments of highly-multiplexed, multi-chroic pixels for Balloon-Borne Platforms

TL;DR

This paper reports on the development of advanced multi-chroic pixels and readout technology for balloon-borne CMB polarization experiments, enhancing multiplexing and sensitivity capabilities.

Contribution

It introduces low thermal conductance bolometers with meandered legs and extends frequency domain multiplexing to 105 channels, improving technology readiness for future satellite missions.

Findings

Achieved 9 pW/K thermal conductance in bolometers.

Extended multiplexing factor to 105 channels.

Demonstrated technology suitability for future satellite applications.

Abstract

We present our work to develop and characterize low thermal conductance bolometers that are part of sinuous antenna multi-chroic pixels (SAMP). We use longer, thinner and meandered bolometer legs to achieve 9 pW/K thermal conductance bolometers. We also discuss the development of inductor-capacitor chips operated at 4 K to extend the multiplexing factor of the frequency domain multiplexing to 105, an increase of 60% compared to the factor currently demonstrated for this readout system. This technology development is motivated by EBEX-IDS, a balloon-borne polarimeter designed to characterize the polarization of foregrounds and to detect the primordial gravity waves through their B-mode signature on the polarization of the cosmic microwave background. EBEX-IDS will operate 20,562 transition edge sensor bolometers spread over 7 frequency bands between 150 and 360 GHz. Balloon and satellite platforms enable observations at frequencies inaccessible from the ground and with higher instantaneous sensitivity. This development improves the readiness of the SAMP and frequency domain readout technologies for future satellite applications.