arXiv subjects

A. Gola

Publications and source records attributed to A. Gola.

At least 19 recordsLinked to original sources

arXiv2026

Construction, commissioning, and performance of the ENUBET demonstrator

A final full-size prototype of the instrumented decay tunnel of ENUBET, referred to as the Demonstrator, was constructed and its performance was tested during the 2022, 2023 and 2024 beam test campaigns at the CERN East Area facility. We demonstrate the full scalability of this specialized longitudinal sampling calorimeter technology, based on iron absorbers and scintillator tiles readout by wavelength-shifting fibers and SiPMs. In addition, we evaluate the channel-by- channel response and the performance in terms of electron energy resolution, linearity, and particle identification capabilities, using charged particle beams with energies up to 5 GeV. A comparison with the predictions of a GEANT4 simulation of the prototype is also presented. The results meet the requirements for neutrino monitoring through lepton identification in the decay tunnel and validate the ENUBET full simulation. Although some limitations have been identified, they can be readily addressed in future developments.

hep-ex↗

arXiv2026

Electron identification and hadron discrimination using Cherenkov radiation in air and SiPMs

This paper presents a method to identify electrons using the Cherenkov light emitted when a charged particle travels in air and photons are detected with a Silicon PhotoMultiplier (SiPM). The analysis is based on a photon-counting approach using SPAD cells and uses data collected during a test beam at CERN PS. The results are well described by a simple Monte Carlo simulation, which further demonstrates that a very good electron identification and a strong pion/hadron rejection could be obtained over a wide momentum range.

hep-ex↗

arXiv2025

Cryogenic characterization of FBK NUV-HD-Cryo 3T SiPM sensors for the DUNE photon detection system

The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino experiment based in the USA and composed of a Near Detector (ND) complex at Fermi National Laboratory (FNAL), and a Far Detector (FD) complex located at the Sanford Underground Research Facility (SURF) $\sim$1300\,km distant. DUNE will study neutrino oscillations looking for unresolved issues of the Standard Model of particle physics (SM) such as CP violation in the leptonic sector, neutrino mass ordering and others, starting from the early 2030s. The FD, with a mass of $\sim$17\,kt, that will exploit both ionization and scintillation signals to detect neutrino interactions with Argon. Scintillating photons in LAr will be detected by the photon detection system (PDS) based on light collectors coupled to Silicon Photomultipliers (SiPMs). During a test campaign, different laboratories of the collaboration performed an investigation of the best SiPM candidates that fulfill the DUNE FD requirements. We identified two models of SiPM, produced by Hamamatsu Photonics K.K. (HPK) and Fondazione Bruno Kessler (FBK), respectively. In this paper, we focus on the FBK selected model showing its main features. We will describe the characterization protocol, the results at both room and cryogenic temperatures and the photon detection efficiency measurements.

physics.ins-det↗

arXiv2025

Sensitivity to low-mass WIMPs with an improved liquid argon ionization response model within the DarkSide programme

Dark matter detection experiments using liquid argon rely on a precise characterization of the ionization response to nuclear recoils, especially in the keV energy range relevant for light dark matter interactions. In this work, we present a comprehensive analysis that combines new measurements from the ReD setup, part of the DarkSide experimental program, with calibration data from DarkSide-50, as well as results from the ARIS and SCENE experiments. These combined datasets enable improved constraints on atomic screening effects in the modeling of the ionization response of liquid argon to nuclear recoils. The analysis is performed within the Thomas-Imel recombination framework adopted in previous DarkSide studies, and is here further constrained by the inclusion of ReD data, which allow the screening function to be determined from calibration measurements. By including the updated ionization model into the DarkSide-50 analysis framework, we obtain stronger exclusion limits on low-mass WIMP interactions, setting new world-leading constraints in the 1-3 GeV/c^2 WIMP mass range. Finally, we recast the sensitivity projections for the upcoming DarkSide-20k detector, demonstrating a significantly enhanced discovery potential for low-mass dark matter candidates.

hep-ex↗

arXiv2025

Measurements of efficiency, timing and response to irradiation for direct detection of charged particles with SiPMs

In this paper the efficiency of direct charged particle detection with different Silicon PhotoMultiplier (SiPM) sensors has been measured to be close to 100%. Time resolution of about 20 ps has also been confirmed for sensors with an active area of around 3x3 mm$^\text{2}$ and a single-cell area of 40 $\mu$m$^\text{2}$. In addition, the SiPM performance after irradiation, in terms of timing response and dark count rate, has been evaluated for sensors with a 1x1 mm$^\text{2}$ area, demonstrating that SiPMs can maintain excellent timing capabilities and a low dark count rate when an appropriate threshold is applied to the signal.

physics.ins-det↗

arXiv2025

Below 100 ps CTR using FastIC+, an ASIC including on-chip digitization for ToF-PET and beyond

This work presents the 8-channel FastIC+, a low-power consumption and highly configurable multi-channel front-end ASIC with internal digitization, for the readout of photo-sensors with picosecond time resolution and intrinsic gain. This ASIC, manufactured in 65 nm CMOS technology, can readout positive or negative polarity sensors and provides a digitized measurement of the arrival time and energy of the detected events with a power consumption of 12.5 mW per channel. On-chip digitization is executed by a Time-to-Digital Converter (TDC) based on a Phase-Locked Loop (PLL) generating 16 phases at 1.28 GHz. The internal TDC introduces a jitter contribution of 31.3 ps FWHM, with minimal impact on timing measurements. When evaluating FastIC+ to readout 3$\times$3 mm$^2$ silicon photomultipliers (SiPMs) with a pulsed laser, we achieved a single-photon time resolution (SPTR) of (98 $\pm$ 1) ps FWHM. We also performed time-of-flight positron emission tomography (ToF-PET) experiments using scintillator crystals of different sizes and materials. With LYSO:Ce,Ca crystals of 2.8$\times$2.8$\times$20 mm$^3$ we obtained a coincidence time resolution (CTR) of (130 $\pm$ 1) ps FWHM. With LGSO crystals of 2$\times$2$\times$3 mm$^3$, a CTR of (85 $\pm$ 1) ps FWHM. To the best of our knowledge, this is the first time that a CTR below 100 ps using on-chip digitization is reported.

physics.ins-det↗

arXiv2025

nuSCOPE: A short-baseline neutrino beam at CERN for high-precision cross-section measurements

A new generation of neutrino cross-section experiments at the GeV scale is crucial in the precision era of oscillation physics and lepton flavor studies. In this document, we present a novel neutrino beam design that leverages the experience and R&D achievements of the NP06/ENUBET and NuTag Collaborations and explore its potential implementation at CERN. This beam enables flux monitoring at the percent level and provides a neutrino energy measurement independent of final state particle reconstruction at the neutrino detector. As a result, it eliminates the two primary sources of systematic uncertainty in cross-section measurements: flux normalization and energy bias caused by nuclear effects. We provide a detailed description of the beam technology and instrumentation, along with an overview of its physics potential, with particular emphasis on cross-sections relevant to DUNE and Hyper-Kamiokande.

hep-ex↗

arXiv2025

The ENUBET monitored neutrino beam and its implementation at CERN

The ENUBET project recently concluded the R&D for a site independent design of a monitored neutrino beam for high precision cross section measurements, in which the neutrino flux is inferred from the measurement of charged leptons in an instrumented decay tunnel. In this phase three fundamental results were obtained and will be discussed here: 1) a beamline not requiring a horn and relying on static focusing elements allows to perform a $\nu_e$ cross section measurement in the DUNE energy range with 1% statistical uncertainty employing $10^{20}$ 400 GeV protons on target (pot) and a neutrino detector of the size of ProtoDUNE; 2) the instrumentation of the decay tunnel, based on a cost effective sampling calorimeter solution, has been tested with a large scale prototype achieving the performance required to identify positrons and muons from kaon decays with high signal-to-noise ratio; 3) the systematics budget on the neutrino flux is constrained at the 1% level by fitting the charged leptons observables measured in the decay tunnel. Based on these successful results ENUBET is now pursuing a study for a site dependent implementation at CERN in the framework of Physics Beyond Colliders. In this context a new beamline, able to enrich the neutrino flux at the energy of HK and to reduce by more than a factor 3 the needed pot, has been designed and is being optimized. The civil engineering and radioprotection studies for the siting of ENUBET in the North Area towards the two ProtoDUNEs are also in the scope of this work, with the goal of proposing a neutrino cross section experiment in 2026. The combined use of both the neutrino detectors and of the improved beamline would allow to perform cross section measurements with unprecedented precision in about 5 years with a proton request compatible with the needs of other users after CERN Long Shutdown 3.

hep-ex↗

arXiv2024

Quality Assurance and Quality Control of the $26~\text{m}^2$ SiPM production for the DarkSide-20k dark matter experiment

DarkSide-20k is a novel liquid argon dark matter detector currently under construction at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) that will push the sensitivity for Weakly Interacting Massive Particle (WIMP) detection into the neutrino fog. The core of the apparatus is a dual-phase Time Projection Chamber (TPC), filled with \SI{50} {tonnes} of low radioactivity underground argon (UAr) acting as the WIMP target. NUV-HD-cryo Silicon Photomultipliers (SiPM)s designed by Fondazione Bruno Kessler (FBK) (Trento, Italy) were selected as the photon sensors covering two $10.5~\text{m}^2$ Optical Planes, one at each end of the TPC, and a total of $5~\text{m}^2$ photosensitive surface for the liquid argon veto detectors. This paper describes the Quality Assurance and Quality Control (QA/QC) plan and procedures accompanying the production of FBK~NUV-HD-cryo SiPM wafers manufactured by LFoundry s.r.l. (Avezzano, AQ, Italy). SiPM characteristics are measured at 77~K at the wafer level with a custom-designed probe station. As of March~2025, 1314 of the 1400 production wafers (94% of the total) for DarkSide-20k were tested. The wafer yield is $93.2\pm2.5$\%, which exceeds the 80\% specification defined in the original DarkSide-20k production plan.

physics.ins-det↗

arXiv2023

Design and performance of the ENUBET monitored neutrino beam

The ENUBET project is aimed at designing and experimentally demonstrating the concept of monitored neutrino beams. These novel beams are enhanced by an instrumented decay tunnel, whose detectors reconstruct large-angle charged leptons produced in the tunnel and give a direct estimate of the neutrino flux at the source. These facilities are thus the ideal tool for high-precision neutrino cross-section measurements at the GeV scale because they offer superior control of beam systematics with respect to existing facilities. In this paper, we present the first end-to-end design of a monitored neutrino beam capable of monitoring lepton production at the single particle level. This goal is achieved by a new focusing system without magnetic horns, a 20 m normal-conducting transfer line for charge and momentum selection, and a 40 m tunnel instrumented with cost-effective particle detectors. Employing such a design, we show that percent precision in cross-section measurements can be achieved at the CERN SPS complex with existing neutrino detectors.

hep-ex↗

arXiv2023

Directionality of nuclear recoils in a liquid argon time projection chamber

The direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a target material from the WIMP elastic scattering. A promising experimental strategy for direct dark matter search employs argon dual-phase time projection chambers (TPC). One of the advantages of the TPC is the capability to detect both the scintillation and charge signals produced by NRs. Furthermore, the existence of a drift electric field in the TPC breaks the rotational symmetry: the angle between the drift field and the momentum of the recoiling nucleus can potentially affect the charge recombination probability in liquid argon and then the relative balance between the two signal channels. This fact could make the detector sensitive to the directionality of the WIMP-induced signal, enabling unmistakable annual and daily modulation signatures for future searches aiming for discovery. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data were taken with 72 keV NRs of known recoil directions. The direction-dependent liquid argon charge recombination model by Cataudella et al. was adopted and a likelihood statistical analysis was performed, which gave no indications of significant dependence of the detector response to the recoil direction. The aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/- 0.027 and the upper limit is R < 1.072 with 90% confidence level

physics.ins-det↗

arXiv2023

Measurements of the Cherenkov effect in direct detection of charged particles with SiPMs

In this paper, different Silicon PhotoMultiplier (SiPM) sensors have been tested with charged particles to characterize the Cherenkov light produced in the sensor protection layer. A careful position scan of the SiPM response has been performed with different prototypes, confirming the large number of firing cells and proving almost full efficiency, with the SiPM filling factor essentially negligible. This study also allowed us to study the time resolution of such devices as a function of the number of firing cells, reaching values below 20 ps. These measurements provide significant insight into the capabilities of SiPM sensors in direct detection of charged particles and their potential for several applications.

physics.ins-det↗

arXiv2022

Understanding the direct detection of charged particles with SiPMs

In this paper evidence that the increased response of SiPM sensors to the passage of charged particles is related mainly to Cherenkov light produced in the protection layer is reported. The response and timing properties of sensors with different protection layers have been studied.

physics.ins-det↗

arXiv2022

SiPM cross-talk in liquid argon detectors

SiPM-based readouts are becoming the standard for light detection in particle detectors given their superior resolution and ease of use with respect to vacuum tube photo-multipliers. However, the contributions of detection noise such as the dark rate, cross-talk, and after-pulsing may impact significantly their performance. In this work, we present the development of highly reflective single-phase argon chambers capable of light yields up to 32 photo-electrons per keV, with roughly 12 being primary photo-electrons generated by the argon scintillation, while the rest are accounted by optical cross-talk. Furthermore, the presence of compound processes results in a generalized Fano factor larger than 2 already at an over-voltage of 5 V. Finally, we present a parametrization of the optical cross-talk for the FBK NUV-HD-Cryo SiPMs at 87 K that can be extended to future detectors with tailored optical simulations.

physics.ins-det↗

arXiv2022

Direct comparison of PEN and TPB wavelength shifters in a liquid argon detector

A large number of particle detectors employ liquid argon as their target material owing to its high scintillation yield and its ability to drift ionization charge over large distances. Scintillation light from argon is peaked at 128 nm and a wavelength shifter is required for its efficient detection. In this work, we directly compare the light yield achieved in two identical liquid argon chambers, one of which is equipped with PolyEthylene Naphthalate (PEN) and the other with TetraPhenyl Butadiene (TPB) wavelength shifter. Both chambers are lined with enhanced specular reflectors and instrumented with SiPMs with a coverage fraction of approximately 1%, which represents a geometry comparable to the future large scale detectors. We measured the light yield of the PEN chamber to be 39.4$\pm$0.4(stat)$\pm$1.9(syst)% of the yield of the TPB chamber. Using a Monte Carlo simulation this result is used to extract the wavelength shifting efficiency of PEN relative to TPB equal to 47.2$\pm$5.7%. This result paves the way for the use of easily available PEN foils as a wavelength shifter, which can substantially simplify the construction of future liquid argon detectors.

physics.ins-det↗

arXiv2022

Very large SiPM arrays with aggregated output

In this work we will document the design and the performances of a SiPM-based photodetector with a surface area of 100 cm$^2$ conceived to operate as a replacement for PMTs. The signals from 94 SiPMs are summed up to produce an aggregated output that exhibits in liquid nitrogen a dark count rate (DCR) lower than 100 cps over the entire surface, a signal to noise ratio better than 13, and a timing resolution better than 5.5 ns. The module feeds about 360 mW at 5 V with a dynamic range in excess of 500 photo-electrons on a 100 $Ω$ differential line. The unit is compatible with operations at room temperature, with a DCR increased by about 6 orders of magnitude.

physics.ins-det↗

arXiv2021

Characterization of Silicon Photomultipliers after proton irradiation up to $10^{12} n_{eq}/mm^2$

Silicon photomultipliers (SiPMs) are highly-sensitive photodetectors emerging as the technology of choice for many applications, including large high-energy physics experiments where they often are exposed to high radiation fluences. In recent years, there has been an increasing interest in assessing the performance deterioration of such detectors after the irradiation with proton or neutron, with different fluence levels. In this work, samples of different FBK SiPM technologies, made with different manufacturing technologies, were irradiated at the INFN-LNS facility (Italy) with protons reaching fluences up to $10^{12}n_{eq}/mm^2$ (1 MeV neutron equivalent) which correspond $10^{14}n_{eq}/cm^2$ to and their performances were characterized in detail after an approximately 30 days room temperature annealing. The results show a significant worsening of the primary noise (dark count rate) of the detectors, which increases with the irradiation dose, whereas the other performance parameters like the micro-cell gain, the correlated noise probability and the photon detection efficiency do not show significant variations over the investigated dose range. The breakdown voltage estimation after irradiation is another important aspect for a SiPM. In this contribution, we show several methods for its estimation and compare the results. We also introduced new methodologies to characterize the performance of the SiPMs when they present a very high level of noise. Lastly, we also analyzed the spatial localization of the proton-induced defects inside the device, i.e. the defects that mostly contribute to the increase of the DCR of the device, through the emission microscopy (EMMI) technique. In particular, we analyzed the SiPMs at the single cell level, trying to identify and spatially localize the defects.

physics.ins-det↗

arXiv2021

Design considerations for a new generation of SiPMs with unprecedented timing resolution

The potential of photon detectors to achieve precise timing information is of increasing importance in many domains, PET and CT scanners in medical imaging and particle physics detectors, amongst others. The goal to increase by an order of magnitude the sensitivity of PET scanners and to deliver, via time-of-flight (TOF), true space points for each event, as well as the constraints set by future particle accelerators require a further leap in time resolution of scintillator-based ionizing radiation detectors, reaching eventually a few picoseconds resolution for sub MeV energy deposits. In spite of the impressive progress made in the last decade by several manufacturers, the Single Photon Time Resolution (SPTR) of SiPMs is still in the range of 70-120ps FWHM, whereas a value of 10ps or even less would be desirable. Such a step requires a break with traditional methods and the development of novel technologies. The possibility of combining the extraordinary potential of nanophotonics with new approaches offered by modern microelectronics and 3D electronic integration opens novel perspectives for the development of a new generation of metamaterial-based SiPMs with unprecedented photodetection efficiency and timing resolution.

physics.ins-det↗