Ponente
Descripción
Ultra-high energy cosmic rays (UHECRs) above 100 PeV can be detected from space by looking towards the Earth's limb, where the optical emission from extensive air showers (EAS) can be observed. Space-based experiments can also play a crucial role in the multi-messenger astrophysics era, particularly through the detection of Earth-skimming neutrinos. Validating the observational techniques used to detect such rare UHE events involves precursor missions such as NUSES: a satellite mission designed to operate in a sun-synchronous, quasi-polar low Earth orbit.
Two payloads will be installed on board the satellite platform, developed by Thales Alenia Space–Italia (TAS-I): Terzina, which is the main focus of this contribution, and ZIRE’, which is dedicated to low-energy cosmic and gamma rays, space weather, and the study of magnetosphere–ionosphere–lithosphere interactions.
The Terzina telescope is a compact Schmidt-Cassegrain Cherenkov instrument designed to observe the Cherenkov light produced by EASs in the Earth's atmosphere. Its focal plane camera is equipped with an array of Silicon Photomultipliers (SiPMs), enabling precise detection of fast optical signals. The instrument is capable of observing two distinct types of events: when pointing above the Earth's limb, it detects EASs generated by UHECRs; when pointing below the limb, it targets upward-going showers produced by Earth-skimming neutrinos.
To evaluate Terzina’s performance, a full Monte Carlo simulation chain has been implemented, including Cherenkov signal modeling, trigger logic, and particle interaction simulations. A key component is the optical validation performed in Geant4 using the dedicated OpticsLibSim library, developed to accurately reproduce the telescope’s optical response.
Studies have focused on the instrument’s aperture and performance, highlighting its effective collection area and angular response — critical parameters for determining sensitivity to UHECRs and neutrinos. These results validate the current design and support the development of future large-scale space-based observatories.
