Implications of Mini-EUSO measurements for a space-based observation of UHECRs

TL;DR

Mini-EUSO, a space-based UV telescope on the ISS, provides valuable data on Earth's night-time UV emissions, informing the future of space-based Ultra-High Energy Cosmic Ray detection and estimating the exposure for upcoming missions.

Contribution

This paper presents the first results from Mini-EUSO's UV measurements and discusses their implications for future space-based UHECR observations.

Findings

Mini-EUSO successfully maps Earth's night-time UV emissions.

Results inform the potential and design of future UHECR space observatories.

Estimated exposure for future missions like M-EUSO is provided.

Abstract

Mini--EUSO (Multiwavelength Imaging New Instrument for the Extreme Universe Space Observatory, known as \emph{UV atmosphere} in the Russian Space Program) is the first mission of the JEM-EUSO program on board the International Space Station. It was launched in August 2019 and it is operating since October 2019 being located in the Russian section (Zvezda module) of the station and viewing our planet from a nadir-facing UV-transparent window. The instrument is based on the concept of the original JEM-EUSO mission and consists of an optical system employing two Fresnel lenses of 25 cm each and a focal surface composed of 36 Multi-Anode Photomultiplier tubes, 64 channels each, for a total of 2304 channels with single photon counting sensitivity and an overall field of view of 44$^\circ \times $44$^\circ$. Mini-EUSO can map the night-time Earth in the near UV range (predominantly between 290 nm and 430 nm), with a spatial resolution of about 6~km and different temporal resolutions of 2.5~$\mu$s, 320~$\mu$s and 41 ms. Mini-EUSO observations are extremely important to better assess the potential of a space-based detector in studying Ultra-High Energy Cosmic Rays (UHECRs) such as K-EUSO and POEMMA. In this contribution we focus the attention on the results of the UV measurements and we place them in the context of UHECR observations from space, namely the estimation of exposure for the planned M-EUSO (Multi-messenger Extreme Universe Space Observatory) mission.