arXiv subjects

Mario Bertaina

Publications and source records attributed to Mario Bertaina.

At least 19 recordsLinked to original sources

arXiv2025

The Cherenkov Camera for the PBR mission

The POEMMA-Balloon with Radio (PBR) mission is a NASA super-pressure balloon experiment designed to advance the detection of ultra-high-energy cosmic rays, high-altitude horizontal air showers, and astrophysical neutrinos. A key instrument of PBR is the Cherenkov Camera (CC), which utilizes a 2048-pixel SiPM camera to detect the optical Cherenkov emission from cosmic-ray-induced air showers and search for upward-going signals indicative of neutrinos. The CC operates in the 320-900 nm spectral range with a 10 ns integration time, leveraging a bi-focal optical design to enhance detection efficiency. The CC enables precise reconstruction of shower trajectories and provides valuable data on cosmic rays' composition and energy distribution. PBR's sub-orbital altitude is particularly advantageous for these measurements, offering a unique vantage point that bridges the observational gap between ground-based and space-based instruments. Additionally, the CC will play a critical role in neutrino searches, detecting tau-lepton decay showers from Earth-skimming neutrinos associated with astrophysical transients. By integrating the CC with fluorescence and radio detection systems, PBR will pioneer a multi-messenger approach to high-energy cosmic phenomena, refining observational techniques for future space-based missions. This contribution will describe the current status of the development of the CC as well as its expected performance.

astro-ph.IM↗

arXiv2025

Implications of Mini-EUSO measurements for a space-based observation of UHECRs

Mini--EUSO (Multiwavelength Imaging New Instrument for the Extreme Universe Space Observatory, known as \emph{UV atmosphere} in the Russian Space Program) is the first mission of the JEM-EUSO program on board the International Space Station. It was launched in August 2019 and it is operating since October 2019 being located in the Russian section (Zvezda module) of the station and viewing our planet from a nadir-facing UV-transparent window. The instrument is based on the concept of the original JEM-EUSO mission and consists of an optical system employing two Fresnel lenses of 25 cm each and a focal surface composed of 36 Multi-Anode Photomultiplier tubes, 64 channels each, for a total of 2304 channels with single photon counting sensitivity and an overall field of view of 44$^\circ \times $44$^\circ$. Mini-EUSO can map the night-time Earth in the near UV range (predominantly between 290 nm and 430 nm), with a spatial resolution of about 6~km and different temporal resolutions of 2.5~$\mu$s, 320~$\mu$s and 41 ms. Mini-EUSO observations are extremely important to better assess the potential of a space-based detector in studying Ultra-High Energy Cosmic Rays (UHECRs) such as K-EUSO and POEMMA. In this contribution we focus the attention on the results of the UV measurements and we place them in the context of UHECR observations from space, namely the estimation of exposure for the planned M-EUSO (Multi-messenger Extreme Universe Space Observatory) mission.

astro-ph.IM↗

arXiv2025

Performance results of the first version of the MIZAR ASIC for the PBR mission

The Multi-channel Intergrated Zone-sampling Analogue-memory based Readout (MIZAR) ASIC is a new type of front-end electronics which has been developed for the detection of the optical Cherenkov signals by Extensive Air Showers directly observed from sub-orbital and orbital altitudes. It sets the stage for a new generation of low-power consuming 64-channel Application-Specific Integrated Circuit (ASIC). The ASIC is implemented in a commercial 65 nm CMOS technology to readout an 8$\times$8 matrix of Silicon Photo-Multipliers (SiPMs). The event is recorded at channel level in an array of 256 cells, each one equipped with an analogue memory, a 12-bits Wilkinson Analog-to-Digital Converter (ADC) and latches running at a sampling rate of 200 MS/s. The converted data are sent off-chip to a Field Programmable Gate Array (FPGA) which controls the digital end-of-column logic of the ASIC and implements the trigger logic. The goal is to employ it for the first time on the POEMMA Balloon with Radio (PBR) NASA mission which is devoted to measure Ultra-High Energy Cosmic Rays (UHECRs) and perform neutrino astronomy from stratospheric altitudes through the detection of atmospheric Cherenkov light. The first version of the MIZAR ASIC has been sent to production and it is now under test at INFN Torino. The results of the preliminary tests related to the characterization of the chip are presented.

hep-ex↗

arXiv2025

The Extreme Universe Observatory on a Super-Pressure Balloon II: Mission, Payload, and Flight

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 $\gtrsim$ 20 PeV very high energy neutrinos that originate from transient and steady astrophysical sources. EUSO-SPB2 was launched from W\=anaka 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 hours, 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.

astro-ph.HE↗

arXiv2025

Ideas and Requirements for the Global Cosmic-Ray Observatory (GCOS)

After a successful kick-off meeting in 2021. two workshops in 2022 and 2023 on the future Global Cosmic-Ray Observatory (GCOS) focused mainly on a straw man design of the detector and science possibilities for astro- and particle physics. About 100 participants gathered for in-person and hybrid panel discussions. In this report, we summarize these discussions, present a preliminary straw-man design for GCOS and collect short write-ups of the flash talks given during the focus sessions.

astro-ph.IM↗

arXiv2024

The EUSO-SPB2 Fluorescence Telescope for the Detection of Ultra-High Energy Cosmic Rays

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~$\mu$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.

astro-ph.IM↗

arXiv2023

Neural Network Based Approach to Recognition of Meteor Tracks in the Mini-EUSO Telescope Data

Mini-EUSO is a wide-angle fluorescence telescope that registers ultraviolet (UV) radiation in the nocturnal atmosphere of Earth from the International Space Station. Meteors are among multiple phenomena that manifest themselves not only in the visible range but also in the UV. We present two simple artificial neural networks that allow for recognizing meteor signals in the Mini-EUSO data with high accuracy in terms of a binary classification problem. We expect that similar architectures can be effectively used for signal recognition in other fluorescence telescopes, regardless of the nature of the signal. Due to their simplicity, the networks can be implemented in onboard electronics of future orbital or balloon experiments.

astro-ph.IM↗

arXiv2023

An end-to-end calibration of the Mini-EUSO detector in space

Mini-EUSO is a wide Field-of-View (FoV, 44$^{\circ}$) telescope currently in operation from a nadia-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), for a total of 2304 pixels working in photon counting mode, in three different time resolutions of 2.5 ${\mu}$s, 320 ${\mu}$s, 40.96 ms operation 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 Mini-EUSO. In this contribution, we present the assembled UV flasher, the operation of the field campaign and the analysis of the obtained data. The result is compared with the overall efficiency computed from the expectations which takes into account the atmospheric attenuation and the parameterization of different effects such as the optics efficiency, the MAPMT detection efficiency, BG3 filter transmittance and the transparency of the ISS window.

astro-ph.IM↗

arXiv2023

Tests and characterisation of the KI trigger for fast events on the EUSO-SPB2 Fluorescence Telescope

The second generation Extreme Universe Space Observatory on a Super-Pressure Balloon (EUSO-SPB2) mission is a stratospheric balloon mission developed within the Joint Exploratory Missions for Extreme Universe Space Observatory (JEM-EUSO) program. The Fluorescence Telescope (FT) is one of the two separate Schmidt telescopes of EUSO-SPB2, which aims at measuring the fluorescence emission of extensive air showers from cosmic rays above the energy of 1 EeV, looking downwards onto the atmosphere from the float altitude of 33 km. The FT measures photons with a time resolution of 1.05 $\mu$s in two different modes: single photon counting (PC) and charge integration (KI). In this paper, we describe the latter and report on the measurements of its characteristics. We also present a new trigger based on this channel, the so-called KI trigger, which allows to measure additional types of events, namely very short and intense light pulses. We report on the tests of this trigger mode in the laboratory and at the TurLab facility, and its implementation in the EUSO-SPB2 mission.

astro-ph.IM↗

arXiv2023

Analysis of EAS-like events detected by the Mini-EUSO telescope

The Mini-EUSO telescope is the first space-based detector of the JEM-EUSO program. It was launched for the International Space Station on August 22$^{nd}$, 2019 to observe from the ISS orbit ($\sim$420 km altitude) various phenomena occurring in the Earth's atmosphere through a UV-transparent window located in the Russian Zvezda Module. The dimension of the window defines and constrains the dimension of the optics, based on a set of two Fresnel lenses of 25 cm diameter each, almost two orders of magnitude smaller than the system foreseen for a larger space-based detector, like the original JEM-EUSO detector or the future POEMMA. As a consequence, the energy threshold of Mini-EUSO is very high, above $10^{21} $eV. Nevertheless, a series of events that resemble the shape and the time duration of EAS-induced events have been detected in Mini-EUSO data. This contribution presents the most interesting cases, showing that the vast majority of the EAS-like events can be traced back to ground sources repeatedly flashing and triggered many times by Mini-EUSO. Some non-repeated EAS-like events are also present. In these cases, it is possible to exclude their cosmic origin through the comparison with simulated events. Since it is clear that those events can not be originated by a UHECR, we decided to rename them "Short Light Transients" or SLTs. Finally, it was possible to associate some of the SLTs with atmospheric activity. This analysis confirms the validity of the JEM-EUSO detection principle and shows that it is possible for a space-based detector to distinguish between events induced by UHECRs and events with a different origin.

astro-ph.IM↗

arXiv2023

Machine Learning for Mini-EUSO Telescope Data Analysis

Neural networks as well as other methods of machine learning (ML) are known to be highly efficient in different classification tasks, including classification of images and videos. Mini- EUSO is a wide-field-of-view imaging telescope that operates onboard the International Space Station since 2019 collecting data on miscellaneous processes that take place in the atmosphere of Earth in the UV range. Here we briefly present our results on the development of ML-based approaches for recognition and classification of track-like signals in the Mini-EUSO data, among them meteors, space debris and signals the light curves and kinematics of which are similar to those expected from extensive air showers generated by ultra-high-energy cosmic rays. We show that even simple neural networks demonstrate impressive performance in solving these tasks.

astro-ph.IM↗

arXiv2022

Development of a cosmic ray oriented trigger for the fluorescence telescope on EUSO-SPB2

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2), in preparation, aims to make the first observations of Ultra-High Energy Cosmic Rays (UHECRs) from near space using optical techniques. EUSO-SPB2 will prototype instrumentation for future satellite-based missions, including the Probe of Extreme Multi-Messenger Astrophysics (POEMMA) and K-EUSO. The payload will consist of two telescopes. The first is a Cherenkov telescope (CT) being developed to quantify the background for future below-the-limb very high energy (E>10 PeV) astrophysical neutrino observations, and the second is a fluorescence telescope (FT) being developed for detection of UHECRs. The FT will consist of a Schmidt telescope, and a 6192 pixel ultraviolet camera with an integration time of 1.05 microseconds. The first step in the data acquisition process for the FT is a hardware level trigger in order to decide which data to record. In order to maximize the number of UHECR induced extensive air showers (EASs) which can be detected, a novel trigger algorithm has been developed based on the intricacies and limitations of the detector. The expected performance of the trigger has been characterized by simulations and, pending hardware verification, shows that EUSO-SPB2 is well positioned to attempt the first near-space observation of UHECRs via optical techniques.

astro-ph.HE↗

arXiv2021

Expected performance of the K-EUSO space-based observatory

K-EUSO is a planned mission of the JEM-EUSO program for the study of ultra-high energy cosmic rays (UHECR) from space, to be deployed on the International Space Station. The K-EUSO observatory consists of a UV telescope with a wide field of view, which aims at the detection of fluorescence light emitted by extensive air showers (EAS) in the atmosphere. The EAS events will be sampled with a time resolution of $\sim$1-2.5 s to reconstruct the entire shower profile with high precision. The detector consisting of $\sim$$10^5$ independent pixels will allow a spatial resolution of $\sim$700 m on ground. From a 400 km altitude, K-EUSO will achieve a large and full sky exposure to sample the highest energy range of the UHECR spectrum. In this contribution, we present estimates of the performance of the observatory: an estimation of the expected exposure and triggered event rate as a function of energy and the event reconstruction performance, including resolution of arrival directions and energy of UHECRs.

astro-ph.HE↗

arXiv2021

Estimation of the exposure of the TUS space-based cosmic ray observatory

The TUS observatory was the first orbital detector aimed at the detection of ultra-high energy cosmic rays (UHECRs). It was launched on April 28, 2016, from the Vostochny cosmodrome in Russia and operated until December 2017. It collected $\sim80,000$ events with a time resolution of 0.8~$\mu$s. A fundamental parameter to be determined for cosmic ray studies is the exposure of an experiment. This parameter is important to estimate the average expected event rate as a function of energy and to calculate the absolute flux in case of event detection. Here we present results of a study aimed to calculate the exposure that TUS accumulated during its mission. The role of clouds, detector dead time, artificial sources, storms, lightning discharges, airglow and moon phases is studied in detail. An exposure estimate with its geographical distribution is presented. We report on the applied technique and on the perspectives of this study in view of the future missions of the JEM-EUSO program.

astro-ph.HE↗

arXiv2021

Overview of the Mini-EUSO $\mu$s trigger logic performance

Mini-EUSO is the first detector of the JEM-EUSO program deployed on the ISS. It is a wide field of view telescope currently operating from a nadir-facing UV-transparent window on the ISS. It is based on an array of MAPMTs working in photon counting mode with a 2.5 $\mu$s time resolution. Among the different scientific objectives it searches for light signals with time duration compatible to those expected from Extensive Air Showers (EAS) generated by EECRs interacting in the atmosphere. Although the energy threshold for cosmic ray showers is above $E>10^{21}$ eV, due the constraints given by the size of the UV-transparent window, the dedicated trigger logic has been capable of the detection of other interesting classes of events, like elves and ground flashers. An overview of the general performance of the trigger system is provided, with a particular focus on the identification of classes of events responsible for the triggers.

astro-ph.IM↗

arXiv2021

Observation of ELVES with Mini-EUSO telescope on board the International Space Station

Mini-EUSO is a detector observing the Earth in the ultraviolet band from the International Space Station through a nadir-facing window, transparent to the UV radiation, in the Russian Zvezda module. Mini-EUSO main detector consists in an optical system with two Fresnel lenses and a focal surface composed of an array of 36 Hamamatsu Multi-Anode Photo-Multiplier tubes, for a total of 2304 pixels, with single photon counting sensitivity. The telescope also contains two ancillary cameras, in the near infrared and visible ranges, to complement measurements in these bandwidths. The instrument has a field of view of 44 degrees, a spatial resolution of about 6.3 km on the Earth surface and of about 4.7 km on the ionosphere. The telescope detects UV emissions of cosmic, atmospheric and terrestrial origin on different time scales, from a few micoseconds upwards. On the fastest timescale of 2.5 microseconds, Mini-EUSO is able to observe atmospheric phenomena as Transient Luminous Events and in particular the ELVES, which take place when an electromagnetic wave generated by intra-cloud lightning interacts with the ionosphere, ionizing it and producing apparently superluminal expanding rings of several 100 km and lasting about 100 microseconds. These highly energetic fast events have been observed to be produced in conjunction also with Terrestrial Gamma-Ray Flashes and therefore a detailed study of their characteristics (speed, radius, energy...) is of crucial importance for the understanding of these phenomena. In this paper we present the observational capabilities of ELVE detection by Mini-EUSO and specifically the reconstruction and study of ELVE characteristics.

astro-ph.HE↗

arXiv2021

Main results of the TUS experiment on board the Lomonosov satellite

The TUS detector was the first space-based mission aimed for ultra-high-energy cosmic ray (UHECR) measurements. The detector was designed to register the fluorescent signal of extensive air showers (EAS) developing in the night atmosphere of Earth in the UV range of 300-400 nm. TUS was launched on board the Lomonosov satellite in April, 2016 and operated till December, 2017. Almost 90 thousand events were recorded during the mission, among them lightning discharges, meteors, transient luminous events, polar lights and anthropogenic signals. Some puzzling bright UV flashes in a clear sky far from possible artificial sources were also registered. Besides this, a number of EAS candidates were found in the TUS database. The majority of candidates analysed so far were recorded above populated areas near airports or similar objects, and the energy of the signals corresponds to at least 1 ZeV if they were generated by an UHECR, which does not allow one to consider these events as UHECRs. We briefly present the main results of the TUS experiment and discuss its importance for the development of the future orbital missions.

astro-ph.HE↗

arXiv2019

Sensitivity to Atypical Tau Initiated Air Showers For a High-Altitude Optical Cherenkov Detector

The ANITA collaboration has recently announced the supposed observation of two upward going cosmic ray showers at earth emergence angles $27^{\circ}$ and $35^{\circ}$ with reconstructed energy $\sim$0.6~EeV. Upward air showers (UAS) are expected from tau leptons resulting from the interaction of astrophysical neutrinos inside the Earth. However, at emergence angles larger than $20^{\circ}$, the probability of tau emergence from a neutrino is less than $10^{-7}$, which makes a standard model explanation for these signals difficult. If confirmed by other experiments, these energetic events would strengthen the argument for physics beyond the standard model. Both the proposed EUSO-SPB2 and the POEMMA instruments will be equipped with optical Cherenkov detectors in order to measure the Cherenkov emission from UAS, which, if aimed low enough below the horizon, could, in principle, capture these events as well. An observation in the Cherenkov channel would help to rule out anthropogenic and other explanations for these events. We present here the sensitivity to the ANITA anamolous events for a balloon based and a satellite based Cherenkov detector, as could be realized in the upcoming EUSO-SPB2 mission and the proposed POEMMA mission, respectively.

hep-ph↗