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Description
NUSES is a pathfinder satellite project containing two detectors, one Tezrina dedicated to studying Ultra High Energy Cosmic Rays above 100 PeV and the Zirè focusing on the study of protons and electrons below 250 MeV and MeV gamma rays.
This work is focused on the description of the Cherenkov camera, composed of SiPMs, for the Terzina telescope.
Cherenkov light produced by Extensive Air Showers induced by Ultra High Energy Cosmic Rays in the atmosphere could be detected from space, thus ensuring huge exposures.
The Terzina telescope is being designed to detect such light. It has an effective surface of about 0.1 m^2 and an equivalent focal lens of about 930 mm with a diameter of the circle containing 80 % of the photons of less than 1 mm^2. The photo-detection plane is composed of 2x5 SiPM arrays with 8x8 channels of 3x3 mm^2 pixels each.
We aim to detect very low light levels keeping the data acquisition dead time as low as 1-2 %. Therefore effective trigger logic is crucial to reach the physics goal of the experiment and is described within this work.
To increase the data-taking period NUSES orbit will be sun-synchronous (with a height of about 550 km) thus allowing Terzina to point always towards the atmosphere limb in the night.
The sun-synchronous orbit requires small distances to the poles and as a consequence the expected dose received by the SiPMs will be 10 Gy per year, while the NUSES mission will last about three years. About 70 % of the integral dose is delivered by the electrons and secondary gammas created in the mechanical structure and about 30 % from protons. This estimation is done with the Geant4 simulation of the preliminary Telescope geometry, using a conservative approach.
The FBK research institute has recently developed low optical cross-talk SiPMs which spectral sensitivity is optimized for Cherenkov light detection. They are the candidate for the implementation of the photon camera. Therefore we study these detectors under the irradiation received by the 50 MeV protons up to 30 Gy of total integrated dose corresponding to the 9 years of the operation.
| Eligibility for "Best presentation for young researcher" prize | No |
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