Speaker
Description
We present the strategy and hardware development for the POLOCALC drone-deployed calibration system for Cosmic Microwave Background. Achieving the unprecedented precision required for next generation CMB experiments, whose goal is the measurement of the inflationary signal due to the primordial gravitational waves. We have developed and deployed artificial sources capable of emitting in multiple bands centered at 90, 150, 220, and 280 GHz, respectively.
Each calibration source emits a stable, monochromatic signal. This controlled signal is used to calibrate the frequency-dependent properties of the telescopes, such as the polarization angle of the detectors and the telescope beam. For the latter, we focus on modelling cross-polar patterns and the natural variation of the beams across the wide observing bands. The sources are mounted on a Unmanned Aerial Vehicle (UAV), or drone, in order to position them accurately in the far-field of the telescopes. This allows for a comprehensive characterization of the instrument’s response, which is crucial for controlling systematic errors in the polarization measurements.
We show results from the drone-borne calibration campaigns performed in the Atacama desert throughout 2025. We also outline the development path towards a dichroic source capable of simultaneously emitting at frequencies of both the 90- and 150-GHz frequency bands, which will further enhance calibration efficiency.
| Parallel session | Astrophysical Probes of Dark Matter and Dark Energy |
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