UCIRC2: EUSO-SPB2's Infrared Cloud Monitor

TL;DR

UCIRC2 is an infrared cloud monitor designed for EUSO-SPB2 to measure cloud coverage and altitude, enhancing the detection capabilities for ultra high energy cosmic rays and neutrinos by reducing observational uncertainties caused by clouds.

Contribution

This paper introduces UCIRC2, a new infrared camera system for cloud monitoring on EUSO-SPB2, including its design, calibration techniques, and integration for improved astrophysical observations.

Findings

UCIRC2 successfully measures cloud-top temperatures and altitudes.

Calibration techniques ensure accurate cloud property measurements.

Enhanced cloud monitoring improves EUSO-SPB2's observational accuracy.

Abstract

The second generation of the Extreme Universe Space Observatory on a Super Pressure Balloon (EUSO-SPB2) is a balloon instrument for the detection of ultra high energy cosmic rays (UHECRs) with energies above 1 EeV and very high energy neutrinos with energies above 10 PeV. EUSO-SPB2 consists of two telescopes: a fluorescence telescope pointed downward for the detection of UHECRs and a Cherenkov telescope pointed towards the limb for the detection of tau lepton-induced showers produced by up-going tau neutrinos and background signals below the limb. Clouds inside the field of view of these telescopes reduce EUSO-SPB2's geometric aperture, in particular that of the fluorescence telescope. For this reason, cloud coverage and cloud-top altitude within the field of view of the fluorescence telescope must be monitored throughout data-taking. The University of Chicago Infrared Camera (UCIRC2) will monitor these clouds using two infrared cameras with response centered at wavelengths 10 and 12 microns. By capturing images at wavelengths spanning the cloud thermal emission peak, UCIRC2 will measure cloud color-temperatures and thus cloud-top altitudes. In this contribution, we provide an overview of UCIRC2, including an update on its construction and a discussion of the techniques used to calibrate the instrument.