arXiv subjects

Francesca Bisconti

Publications and source records attributed to Francesca Bisconti.

13 recordsLinked to original sources

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 $μ$s, 320 $μ$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.

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arXiv2023

Study of the upgraded EUSO-TA performance via simulations

The EUSO-TA ground-based fluorescence detector of the JEM-EUSO program, which operates at the Telescope Array (TA) site in Utah (USA), is being upgraded. In the previous data acquisition campaigns, it detected the first nine ultra-high energy cosmic ray events with the external trigger provided by the Black Rock Mesa fluorescence detectors of the Telescope Array (TA-BRM-FDs). Among the upgrades, there is the installation of a trigger algorithm for the independent detection of cosmic ray air showers and upgraded electronics. A simulation study was developed to understand the performance of EUSO-TA in the new setup and different background conditions. This study allowed us to estimate the detection limit of the ground-based detector, which can be used to extrapolate the detection limit for a balloon-based detector. Moreover, it provided estimations of the expected trigger rates for ultra-high energy cosmic rays. In this work, the description of the simulation setup, the method developed to rescale the energy of the cosmic rays to account for the portion of air shower actually observed rather than the whole one, and the results in terms of detection limit and trigger rates, are reported.

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arXiv2023

A prototype tank for the SWGO detector

The Southern Wide-field Gamma-ray Observatory (SWGO) is an international collaboration working on realizing a next-generation observatory located in the Southern hemisphere, which offers a privileged view of our galactic center. We are working on the construction of a prototype water Cherenkov detector at Politecnico di Milano using a flexible testing facility for several candidate light sensors and configurations. A structure able to hold different types of detectors in multiple configurations has been designed, built and tested in Politecnico's labs. Furthermore, an analytical study of muons and electrons showers has been carried out using the SWGO observatory simulation software to examine the correlation between the detection capabilities of the prototype tank and its water level.

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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.

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arXiv2022

Study of water Cherenkov detector design for ground-based gamma-ray experiments

In the framework of the development of the SWGO experiment we have performed a detailed study of the single unit of an extensive air shower observatory based on an array of water Cherenkov detectors. Indeed, one of the possible water Cherenkov detector unit configurations for SWGO consists of tanks, and to reach a high detection efficiency and discrimination capability between gamma-ray and hadronic air showers, different tank designs are under investigation. In this study, we considered double-layer tanks with several sizes, shapes and number of photo-multiplier tubes (PMTs). Muons, electrons, and gamma-rays with energies typical of secondary particles in extensive air showers have been simulated entering the tanks with zenith angles from 0 to 60 degrees. The tank response was evaluated considering the number of photoelectrons produced by the PMTs, the detection efficiency, and the time resolution of the measurement of the first photon. This analysis allowed to compare the performance of tanks with different size, configuration of PMTs, and with circular, hexagonal and square geometry. The method used and the results will be discussed in this paper.

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arXiv2021

Overview of the Mini-EUSO $μ$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 $μ$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.

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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↗

arXiv2019

A More Complete Phenomenology of Tau Lepton Induced Air Showers

Many proposed and upcoming experiments seek to observe signals from upward going air showers initiated by tau leptons resulting from neutrino interactions inside the Earth. To save calculation time, event estimations for these observation methods are usually performed while making several assumptions about the showers themselves, which simplifies their rich phenomenology and may or may not lead to inaccuracies in results. Here, we present results of extensive CORSIKA simulations of upward going tau initiated showers in the energy range 1 PeV to 10 EeV. Specifically, we monitor the Cherenkov emission, the charged particle distributions, and the timing of the showers for different geometric configurations. We analyze the impact of the decay length and different decay modes of the tau on particle distributions and compare to primaries usually utilized to simulate a tau shower, such as gammas, electrons, and protons. We also check the accuracy of many of the usual assumptions of these showers and analyze the often ignored muon channel of the tau decay.

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arXiv2019

Laser test with Mini-EUSO

Mini-EUSO (Extreme Universe Space Observatory) is a small-scale prototype cosmic-ray detector that will measure Earth`s UV emission and other atmospheric phenomena from space. It will be placed in the International Space Station (ISS) behind a UV-transparent window looking to the nadir. The launch is planned this year (2019). Consisting of a multi-anode photomultiplier (MAPMT) camera and a $25$ cm diameter Fresnel lens system, Mini-EUSO has a \ang{44} field of view (FoV), a $6.5$ km$^2$ spatial resolution on the ground and a $2.5\ μ$s temporal resolution. In principle, Mini-EUSO will be sensitive to extensive air shower (EAS) from cosmic-rays with energies above $10^{21}$ eV. A mobile, steerable UV laser system will be used to test the expected energy threshold and performance of Mini-EUSO. The laser system will be driven to remote locations in the Western US and aimed across the field of view of Mini-EUSO when the ISS passes overhead during dark nights. It will emit pulsed $355$ nm UV laser light to produce a short speed-of-light track in the detector. The brightness of this track will be similar to the track from an EAS resulting from a cosmic-ray of up to $10^{21}$ eV. The laser energy is selectable with a maximum of around $90$ mJ per pulse. The energy calibration factor is stable within $5\ \% $. The characteristics of the laser system and Mini-EUSO have been implemented inside the JEM-EUSO OffLine software framework, and laser simulation studies are ongoing to determine the best way to perform a field measurement.

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arXiv2019

Machine Learning Approach for Air Shower Recognition in EUSO-SPB Data

The main goal of The Extreme Universe Space Observatory on a Super Pressure Balloon (EUSO-SPB1) was to observe from above extensive air showers caused by ultra-high energy cosmic rays. EUSO-SPB1 uses a fluorescence detector that observes the atmosphere in a nadir observation mode from a near space altitude. During the 12-day flight, an onboard first level trigger detected more than \num{175000} candidate events. This paper presents an approach to recognize air showers in this dataset. The approach uses a feature extraction method to create a simpler representation of an event and then it uses established machine learning techniques to classify data into at least two classes - shower and noise. The machine learning models are trained on a set of air shower simulations put on top of the background observed during the flight and a set of events from the flight. We present the efficiency of the method on datasets of simulated events. The flight data events are also used in unsupervised learning methods to identify groups of events with similar features. The presented methods allow us to shorten the candidate events list and, thanks to the groups of similar events identified by the unsupervised methods, the classification of the triggered events is made simpler.

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arXiv2018

Characterization of Hamamatsu 64-channel TSV SiPMs

The Hamamatsu UV-light enhanced 64-channel SiPM array of the newest generation (S13361-3050AS-08) has been examined for the purpose of being used for the Silicon Elementary Cell Add-on (SiECA) of the EUSO-SPB balloon experiment. Characterization measurements have been performed with the newly installed Single Photon Calibration Stand at KIT (SPOCK). The results of the characterization measurements including the breakdown voltage, the gain, the PDE, the dark-count rate and the crosstalk probability of all 64 SiPM channels are presented. Additional measurements of the SiPM sensitivity to photons with wavelengths lower than 400nm show an improved PDE for small wavelengths compared to the SiPM array S12642-0808PA-50, which was also investigated for comparison. The response dynamics have been investigated for low numbers of incoming photons. Temperature dependent measurements of the gain, the PDE, the dark-count rate and the crosstalk probability have been performed for one channel of the SiPM array.

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arXiv2017

EUSO-TA fluorescence detector

EUSO-TA is a pathfinder experiment for the space based JEM-EUSO mission for the detection of ultra-high energy cosmic rays. EUSO-TA is an high-resolution fluorescence telescope installed in front of the Black Rock Mesa fluorescence detectors of the Telescope Array (TA) experiment, in Utah (USA). At the TA site, a Central Laser Facility is installed for calibration purposes, since it emits laser beams with known energy and geometry. EUSO-TA consists of two 1 $\mbox{m}^2$ Fresnel lenses, with a field of view of 10.5° that focus the light on a Photo Detector Module (PDM). The PDM currently consists of 36 Hamamatsu Multi-Anode Photo-Multipliers Tubes (MAPMTs) with 64 channels each. Front-end readout is performed by 36 ASICS, with two FPGA boards that send the data to a CPU and a storage system. The detector was installed in February 2015. Tests using the mentioned light sources have been performed and observations of cosmic ray events, as well as those of stars with different magnitude and color index have been done. The data acquisition is triggered by TA fluorescence detectors, although a self-trigger algorithm is currently in the last phases of development and test. With TA, thanks to its large field of view and the surface detectors, the cosmic ray shower events are reconstructed and the parameters are used to perform simulations of the response of EUSO-TA detector using EUSO-Offline. Simulations of the detected events are compared with data and the results are shown in this work.

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