An end-to-end in-flight calibration of Mini-EUSO detector

¹ Gran Sasso Science Institute, Viale Francesco Crispi 7, 67100 l’Aquila, Italy
² INFN Section of Turin, Via P. Giuria 1, 10125 Turin, Italy
³ Department of Physics, University of Turin, Via P. Giuria 1, 10125 Turin, Italy
⁴ INAF Astrophysics Observatory of Turin, Via Osservatorio 20, 10025 Pino Torinese, Italy
⁵ Faculty of Phyiscs, M.V.Lomonosov Moscow State University, ul. Kolmogorova 1(2), 119234 Moscow, Russia
⁶ Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State Univ., ul. Kolmogorova 1(2), 119234 Moscow, Russia
⁷ INFN Section of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
⁸ RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan
⁹ Université Paris Cité, CNRS, Astroparticule et Cosmologie, 10 Rue Alice Domon et Lèonie Duquet, 75013 Paris, France
¹⁰ KTH Royal Institute of Technology, Brinellvägen 8, 114 28 Stockholm, Sweden
¹¹ Department of Physics, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
¹² Technical University of Munich, Arcisstraße 21, 80333 Munich, Germany
¹³ S.P. Korolev Rocket and Space Corporation Energia, Lenin str., 4a Korolev, 141070 Moscow area, Russia
¹⁴ ASI, Italian Space Agency, Via del Politecnico, 00133 Rome, Italy
¹⁵ Omega, Ecole Polytechnique, CNRS/IN2P3, Rte de Saclay, 91120 Palaiseau, France
¹⁶ Department of Astronomy and Astrophysics, The University of Chicago, 5640 S. Ellis Avenue, Chicago IL 60637, US
¹⁷ Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
¹⁸ Department of Physics, Colorado School of Mines, 1523 Illinois St., Golden CO 80401, US
¹⁹ INFN National Laboratories of Frascati, Via Enrico Fermi 54, 00044 Frascati, Italy
²⁰ Department of Physics, Konan University, 8 Chome-9-1 Okamoto, Higashinada Ward Kobe, Hyogo 658-8501, Japan
²¹ National Centre for Nuclear Research, 28 Pułku Strzelców Kaniowskich 69, 90-558 Łódź, Poland
²² Faculty of Physics, University of Warsaw, Ludwika Pasteura 5, 02-093 Warsaw, Poland

^* email: miyamoto@to.infn.it
^** email: matteo.battisti@to.infn.it

Published online: 28 April 2023

Abstract

Mini-EUSO is a wide Field-of-View (FoV, 44°) telescope currently in operation from a nadir-facing UV-transparent window in the Russian Zvezda module on the International Space Station (ISS). It is the first detector of the JEM-EUSO program deployed on the ISS, launched in August 2019. The main goal of Mini-EUSO is to measure the UV emissions from the ground and atmosphere, using an orbital platform. Mini-EUSO is mainly sensitive in the 290–430 nm bandwidth. Light is focused by a system of two Fresnel lenses of 25 cm diameter each on the Photo-Detector-Module (PDM), which consists of an array of 36 Multi-Anode Photomultiplier Tubes (MAPMTs), arranged in blocks of 2 × 2 called Elementary Cells (ECs), for a total of 2304 pixels working in photon counting mode, in three different time resolutions of 2.5 µs (defined as 1 Gate Time Unit, GTU), 320 µs and 40.96 ms operating in parallel. In the longest time scale, the data is continuously acquired to monitor the UV emission of the Earth. It is best suited for the observation of ground sources and therefore has been used for the observational campaigns of the ground-based UV flasher in order to perform an end-to-end calibration of Mini-EUSO. In this contribution, the assembled UV flasher, the operation of the field campaign and the analysis of the obtained data are presented. The result is compared with the overall effi ciency computed from the expectations which takes into account the atmospheric attenuation and the parametrisation of different effects such as the optics effi ciency, the MAPMT detection effi ciency, BG3 filter transmittance and the transparency of the ISS window.