The EUSO-SPB2 Fluorescence Telescope for the Detection of Ultra-High Energy Cosmic Rays
Creators: name: Adams, James H.
name: Allard, Denis
name: Alldredge, Phillip
name: Anchordoqui, Luis
name: Anzalone, Anna
name: Battisti, Matteo
name: Belov, Alexander A.
name: Bertaina, Mario
name: Bertone, Peter F.
name: Blin-Bondil, Sylvie
name: Burton, Julia
name: Cafagna, Francesco S.
name: Casolino, Marco
name: Černý, Karel
name: Christ, Mark J.
name: Colalillo, Roberta
name: Crawford, Hank J.
name: Creusot, Alexandre
name: Cummings, Austin
name: Diesing, Rebecca
name: Di Nola, Alessandro
name: Ebisuzaki, Toshikazu
name: Eser, Johannes
name: Ferrarese, Silvia
name: Filippatos, George
name: Finch, William W.
name: Flaminio, Flavia
name: Fornaro, Claudio
name: Fuehne, Duncan
name: Fuglesang, Christer
name: Garg, Diksha
name: Golzio, Alessio
name: Guarino, Fausto
name: Guépin, Claire
name: Heibges, Tobias
name: Judd, Eleanor G.
name: Klimov, Pavel A.
name: Krizmanic, John F.
name: Kungel, Viktoria
name: Kupari, Luke
name: Kuznetsov, Evgeny
name: Manfrin, Massimiliano
name: Marszal, Wlodzimierz
name: Matthews, John N.
name: Mese, Marco
name: Meyer, Stephan S.
name: Mignone, Marco
name: Miyamoto, Hiroko
name: Murashov, Alexey S.
name: Nachtman, Jane M.
name: Olinto, Angela V.
name: Onel, Yasar
name: Osteria, Giuseppe
name: Panico, Beatrice
name: Parizot, Ètienne
name: Paul, Tom
name: Pech, Miroslav
name: Perfetto, Francesco
name: Piotrowski, Lech W.
name: Plebaniak, Zbigniew
name: Posligua, Jonatan
name: Prévôt, Guillaume
name: Przybylak, Marika
name: Reardon, Patrick
name: Reno, Mary Hall
name: Ricci, Marco
name: Sarazin, Fred
name: Schovánek, P.
name: Scotti, Valentina
name: Shinozaki, Kenji
name: Soriano, Jorge F.
name: Stillwell, Ben K.
name: Szabelski, Jacek
name: Takizawa, Yoshiyuki
name: Trofimov, Daniil
name: Unel, Fredrik
name: Valore, Laura
name: Venters, Tonia M.
name: Watts, John
name: Wiencke, Lawrence
name: Wistrand, Hannah
name: Young, Roy
Publisher: name: arXiv
Year: 2024
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) flew on May 13$^{\text{th}}$ and 14$^{\text{th}}$ of 2023. Consisting of two novel optical telescopes, the payload utilized next-generation instrumentation for the observations of extensive air showers from near space. One instrument, the fluorescence telescope (FT) searched for Ultra-High Energy Cosmic Rays (UHECRs) by recording the atmosphere below the balloon in the near-UV with a 1~$μ$s time resolution using 108 multi-anode photomultiplier tubes with a total of 6,912 channels. Validated by pre-flight measurements during a field campaign, the energy threshold was estimated around 2~EeV with an expected event rate of approximately 1 event per 10 hours of observation. Based on the limited time afloat, the expected number of UHECR observations throughout the flight is between 0 and 2. Consistent with this expectation, no UHECR candidate events have been found. The majority of events appear to be detector artifacts that were not rejected properly due to a shortened commissioning phase. Despite the earlier-than-expected termination of the flight, data were recorded which provide insights into the detectors stability in the near-space environment as well as the diffuse ultraviolet emissivity of the atmosphere, both of which are impactful to future experiments.