Space-based Extensive Air Shower Optical Cherenkov and Fluorescence Measurements using SiPM Detectors in context of POEMMA

TL;DR

POEMMA is a NASA mission using two spacecraft with SiPM-based telescopes to detect ultra-high energy cosmic rays and neutrinos via air shower observations, offering new capabilities in multi-messenger astrophysics.

Contribution

This paper presents the design and implementation of SiPM detectors in POEMMA, comparing their performance to traditional MAPMTs for EAS fluorescence measurements.

Findings

SiPMs offer wide wavelength sensitivity for EAS detection.

Comparison shows SiPMs can perform comparable or better than MAPMTs.

POEMMA's design enables high-statistics UHECR and neutrino observations.

Abstract

Developed as NASA Astrophysics Probe-class mission, the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to identify the sources of ultra-high energy cosmic rays (UHECRs) and to observe cosmic neutrinos. POEMMA consists of two spacecraft flying in a loose formation at 525 km altitude, 28.5$^\circ$ inclination orbits. Each spacecraft hosts a Schmidt telescope with a large collecting area and wide Field-of-View (FoV). A novel focal plane is employed that is optimized to observe both the UV fluorescence signal from extensive air showers (EASs) and the optical Cherenkov signals from EASs. In UHECR stereo fluorescence mode, POEMMA will measure the spectrum, composition, and full-sky distribution of the UHECRs above 20 EeV with high statistics along with remarkable sensitivity to UHE neutrinos. The POEMMA spacecraft are designed to quickly re-orient to a Target-of-Opportunity (ToO) neutrino mode to observe transient astrophysical sources with unique sensitivity. In this mode, POEMMA will be able to detect cosmic tau neutrino events above 20 PeV by measuring the upward-moving EASs for $\tau$-lepton decays induced from tau neutrino interactions in the Earth. In this paper, POEMMA's science goals and instrument design are summarized with a focus on the SiPM implementation in POEMMA, along with a detailed discussion of the properties of the Cherenkov EAS signal in the context of wide wavelength sensitivity offered by SiPMs. A comparison of the fluorescence response between SiPMs and the MAPMTs currently planned for use in POEMMA will also be discussed, assessing the potential for SiPMs to perform EAS fluorescence measurements.