The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) is a pathfinder mission toward a space-based observatory such as the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). The aim of POEMMA is the observation of Ultra High Energy Cosmic Rays (UHECRs) in order to elucidate their nature and origins and to discover ≳ 20 PeV very high energy neutrinos that originate from transient and steady astrophysical sources. EUSO-SPB2 was launched from Wānaka New Zealand on May 13th, 2023 as a NASA Balloon Program Office test flight. The mission goals included making the first near-space altitude observations of the fluorescence emission from UHECR-induced extensive air showers (EASs) and making the first direct Cherenkov light emission from PeV cosmic rays traversing Earth’s atmosphere. In addition, a Target of Opportunity program was developed for selecting and scheduling observations of potential neutrino sources as they passed just below the Earth’s limb. Although a leaky balloon forced termination over the Pacific Ocean after 37 h, data was collected to demonstrate the successful commissioning and operation of the instruments. This paper includes a description of the payload and the key instruments, pre-flight instrument characterizations in the lab and in the desert, flight operations and examples of the data collected. The flight was too short to catch a UHECR event via fluorescence, however about 10 candidate EAS events from cosmic rays were recorded via Cherenkov light.

The Fluorescence Telescope is one of the two telescopes on board the Extreme Universe Space Observatory on a Super Pressure Balloon II (EUSO-SPB2). EUSO-SPB2 is an ultra-long-duration balloon mission that aims at the detection of Ultra High Energy Cosmic Rays (UHECR) via the fluorescence technique (using a Fluorescence Telescope) and of Ultra High Energy (UHE) neutrinos via Cherenkov emission (using a Cherenkov Telescope). The mission is planned to fly in 2023 and is a precursor of the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). The Fluorescence Telescope is a second generation instrument preceded by the telescopes flown on the EUSO-Balloon and EUSO-SPB1 missions. It features Schmidt optics and has a 1-meter diameter aperture. The focal surface of the telescope is equipped with a 6912-pixel Multi Anode Photo Multipliers (MAPMT) camera covering a 37.4 x 11.4 degree Field of Regard. Such a big Field of Regard, together with a flight target duration of up to 100 days, would allow, for the first time from suborbital altitudes, detection of UHECR fluorescence tracks. This contribution will provide an overview of the instrument including the current status of the telescope development.

The JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) collaboration constructs a series of balloon and orbital telescopes to detect fluorescent UV emission from the Earth atmosphere, with the primary aim to study ultra-high-energy cosmic rays (UHECRs) from space. The detectors have wide field-of-view (more than 20 degrees FOV), high temporal resolution (1-2.5 µs) and high sensitivity provided by a large aperture. Currently, one of these detectors is operating onboard the International Space Station (Mini-EUSO). The next one is planned to be launched in the spring of 2023 (EUSO-SPB2) and another one is in preparation stage (K-EUSO). These projects use the same photo-detection modules (PDMs) composed of 36 multi-anode photomultiplier tubes (MAPMTs), each with 64 pixels, for a total of 2304 pixels. Mini-EUSO uses one PDM, EUSO-SPB2 uses three and the future full-scale missions will use several tens of PDMs. In the process of preparing and testing of PDMs, a new technique was developed to characterize their performance and provide absolute calibration of the MAPMTs used in the different JEM-EUSO missions. The method provides the efficiency of each pixel (including the sub-pixel structures), as well as the actual area occupied by the different pixels on the photocathode of the MAPMT. The method and its application to EUSO-SPB2 PDMs at different high voltages and in different modes of operation are presented.

K-EUSO (KLYPVE-EUSO) is a planned orbital mission aimed at studying ultra-high energy cosmic rays (UHECRs) by detecting fluorescence and Cherenkov light emitted by extensive air showers in the nocturnal atmosphere of Earth in the ultraviolet (UV) range. The observatory is being developed within the JEM-EUSO collaboration and is planned to be deployed on the International Space Station after 2025 and operated for at least two years. The telescope, consisting of ∼105 independent pixels, will allow a spatial resolution of ∼0.6 km on the ground, and, from a 400 km altitude, it will achieve a large and full sky exposure to sample the highest energy range of the UHECR spectrum. We provide a comprehensive review of the current status of the development of the K-EUSO experiment, paying special attention to its hardware parts and expected performance. We demonstrate how results of the K-EUSO mission can complement the achievements of the existing ground-based experiments and push forward the intriguing studies of ultra-high energy cosmic rays, as well as bring new knowledge about other phenomena manifesting themselves in the atmosphere in the UV range.

The SPACIROC ASIC is designed for the JEM-EUSO fluorescence imaging telescope onboard of the International Space Station. Its goal is the detection of Giant Air Shower above a few 10^19eV, developing at a distance of about 400km, downward in the troposphere. From such distance, most of the time, the number of the photons expected in the pixels is very weak, ranging from a few units to a few tens. For such running conditions, we propose a low-power, rad-hard ASIC which is intended for reading out a 64-channel Multi-Anode Photomultiplier. The two main features of this ASIC are the photon counting mode for each input and the charge-to-time (Q-to-T) conversions for the multiplexed channels. In the photon counting mode, the 100% triggering efficiency is achieved for 50 fC input charges. For the Q-to-T converter, the ASIC requires a minimum input of 2 pC. The working conditions of JEM-EUSO require the ASIC to have a low power dissipation which is around 1mW/channel. The design of SPACIROC and the test results are presented in this paper. SPACIROC is a result of the collaboration between OMEGA/LAL-Orsay, France, RIKEN, ISAS/JAXA and Konan University, Japan on behalf of the JEM-EUSO consortium.

The SPACIROC ASIC is designed for the JEM-EUSO observatory onboard of the International Space Station (ISS). The main goal of JEM-EUSO is to observe Extensive Air Shower (EAS) produced in the atmosphere by the passage of the high energetic extraterrestrial particles above a few 10(19) eV. A low-power, rad-hard ASIC is proposed for reading out the 64-channel Multi-Anode Photomultipliers which are going to equip the detection surface of JEM-EUSO. The two main features of this ASIC are the photon counting mode for each input and the charge-to-time (Q-to-T) conversion for the multiplexed channels. In the photon counting mode, the 100% triggering efficiency is achieved for 50 fC input charges. For the Q-to-T converter, the ASIC requires a minimum input of 2 pC. In order to comply with the strict power budget available from the ISS, the ASIC is needed to dissipate less than 1 mW/channel. The design of SPACIROC and the test results are presented in this paper.

The University of Pisa and INFN Pisa are developing a prototype of a small animal PET tomograph employing continuous LYSO crystals and silicon photom ultiplier (SiPM) matrices as photodetectors. The Center for Scientific and Technological Research (FBK-irst) has developed monolithic, 64 pixel SiPM matrices for their use in the PET scanner. The IFIC-Valencia collaborates in the characterization of the first detector heads, and in the construction of a first prototype for proof of concept. The detector heads are composed of continuous 12 mm × 12 mm × 5 mm LYSO crystals coupled to the matrices. The characterization of the detectors has been completed, and a first test prototype consisting of two rotating heads has been developed, assessing the feasibility of operating the system.

The University of Pisa and INFN Pisa are developing a small animal PET prototype scanner employing continuous LYSO crystals and the silicon photomultiplier (SiPM) matrices fabricated at FBK-irst. The SiPM matrices have 64 SiPM pixel elements in a common substrate. The SiPM elements are 1.4 mm × 1.5 mm size, in a 1.5 mm × 1.5 mm pitch. The test of the first detector heads is taking place in collaboration with IFIC, Valencia. The detectors consist of a LYSO crystal of 12 mm × 12 mm coupled to a SiPM matrix. Characterization and position determination tests have been carried out. The energy resolution obtained is 14.5% FWHM at 511 keV. The spatial resolution with center-of-gravity algorithms is 0.9 mm FWHM. A Maximum likelihood method is also being tested. This method allows to separate points at 1 mm distance, and to reconstruct correctly the interaction position also at the edges of the detector.

A high resolution small animal PET scanner that employs Silicon Photomultiplier (SiPM) matrices as photodetectors is under development at the University of Pisa and INFN Pisa. The first SiPM matrices fabricated by the Center for Scientific and Technological Research, FBK-irst (Trento, Italy), are being evaluated for this purpose. The devices are composed of 16 (4 times4) pixel elements of 1 mmtimes1 mm in a common substrate. The first tests have been carried out employing the ASIC MAROC2 for the readout. Energy and timing resolution, and position determination tests have been performed coupling both pixellated and continuous LYSO scintillator crystals to the matrix, and the results have been compared with the ones obtained for single SiPMs. The first tests on position determination with continuous crystals and SiPM matrices have been performed. An intrinsic spatial resolution of 0.61 mm FWHM has been obtained.

A high resolution small animal PET scanner that employs Silicon Photomultiplier (SiPM) matrices as photodetectors is under development at the University of Pisa. The first SiPM matrices fabricated by the Center for Scientific and Technological Research, FBK-irst, Trento, Italy, are being evaluated for this purpose. The devices are composed of 16 (4×4) pixel elements of 1 mm × 1 mm in a common substrate. The first tests have been carried out employing the ASIC MAROC2 for the readout. Energy and timing resolution, and position determination tests have been carried out coupling both pixellated and continuous LYSO scintillator crystals to the matrix, and the results have been compared with the ones obtained for single SiPMs.