The workshop, the fourth of a series that began in 2014, intends to gather the entire INFN community interested and involved in developing future detectors. This meeting offers a space for discussion to strengthen skills, following the European Strategy for Particle Physics recommendations. The detector research and development roadmap will be examined, taking into account new technologies, to prepare the next generations to face future challenges, in line with international strategies.
The aim in this edition of IFD is to compare perspectives on different experimental techniques, including innovations in terms of detector materials and infrastructures, without neglecting the topic of skill development. We would like to verify, through an in-depth discussion, the potential for collaboration and synergy between different R&D lines, promoting exchange with industry and other research centers and national structures.
The workshop will be dedicated to the various aspects of a field that has always been of great interest to the INFN. In each session, the discussion will be triggered by plenary presentations prepared by a group of experts in different fields, then ample space for discussion, adding short presentations in the "rapid-fire" style, as an opportunity to contribute ideas and suggestions - hopefully from part of young people - on each technology. The small expert groups will be ready to gather further suggestions from the community. We intend to leave ample space for discussion to analyze prospects and identify useful elements for planning the future.
Riassunto del workshop INFN del 4 Febrraio 2025 https://agenda.infn.it/event/44313/timetable/
https://agenda.infn.it/event/44098/
Superconducting circuits have proven to be one of the most promising platforms for quantum computing and sensing applications with Josephson junctions as one of their fundamental building blocks. Therefore, a reliable fabrication process and characterization apparatus of these components is of crucial importance for every experimental group in this field.
Traditional characterization of these components consists in a study of their Current-Voltage (IV) characteristic. Measurement setups typically rely on commercial functions generators and oscilloscopes to bias and read the response of the junction, respectively. These instruments, despite being user-friendly, are often very expensive if one wishes to reach a high resolution and dynamic range.
In this contribution we present an alternative, amplification-free approach. Based on a sound-card designed for high-fidelity music applications which, for a fraction of the cost of oscilloscopes and function generators, offers a high resolution and dynamic range. The selected sound-card is designed to be integrated with a Raspberry Pi single-board computer making it easily configurable. We have verified the functionality of our approach characterizing cross-type Al/Al-Ox/Al Josephson junctions microfabricated at FBK.
Superconducting transmon qubits have emerged as powerful tools for precision sensing
applications [1, 2], particularly in the search for light dark matter candidates such as axions
and hidden photons [3–9]. These weakly interacting particles may leave detectable signatures
through their coupling to electromagnetic fields, making highly sensitive quantum devices
essential for their discovery. Transmon qubits, with their exceptional coherence properties
and strong interaction with microwave photons, offer a unique approach to detecting such
exotic weak signals.
In this contribution, we describe how transmon qubits can be employed as quantum sensors
for light dark matter detection, focusing on their role in probing weak microwave signals that
could originate from axion-photon or hidden photon conversions. We then present our efforts
to design, simulate, and validate transmon qubit parameters with the goal of developing a
light dark matter detector.
To achieve this, we employed state-of-the-art simulation techniques such as the Lumped
Oscillator Model [10] and the Energy Participation Ratio method [11] to accurately predict
the key parameters of fixed-frequency and tunable transmon qubits. These parameters include
transition frequencies, anharmonicity, and coupling strengths, all of which are crucial for
maximizing sensitivity to potential dark matter-induced signals.
We then conducted cryogenic measurements of fabricated qubits and compared their ex-
perimental performance with theoretical predictions. The measurements focused on qubit
coherence times, transition frequencies, couplings, as these properties directly impact the de-
tection sensitivity to weak electromagnetic signals. Our results indicate a strong correlation
between simulated and experimental data. However, deviations caused by fabrication-induced
inhomogeneities and setup limitations highlight the need for further refinements in device
engineering.
Future efforts will focus on improving fabrication processes and refining theoretical models
to further enhance detection sensitivity and mitigate sources of noise.
Devices and methods of quantum information science can bring significant upgrades to current and future particle physics detectors. In particular, I will discuss experiments testing the hypothesis that dark matter is composed of very light particles, detectable as an effective field with a specific frequency set by their mass. As the signal to noise ratio is very poor in these experiments, new technologies need to be developed and tested, including superconducting circuits like Josephson parametric amplifiers and microwave single photon detectors (SMPD). With SMPDs, the speed at which most detectors probe the open parameter space at relevant sensitivity can largely be enhanced, and I will report about recent results obtained by applying a transmon-based microwave photon counter to the readout of a cavity haloscope.
Ref https://arxiv.org/abs/2403.02321
The challenges of modern fundamental physics lie in low energy phenomena, such as gravitational waves, cosmological inflation and dark matter. Indeed, different phenomena in astronomy (such as radio burst sources, cosmic microwave background, and GHz-peaked radio sources) need the development of sensitive bolometers operating in the GHz-THz bands. Furthermore, low energy particle physics requires single-photon detectors operating in the sub-visible bands down to a few GHz for the detection of dark photons, axions and weakly interacting massive particles. Indeed, state-of-the-art detectors for fundamental physics are mainly based on transition-edge sensors and kinetic inductance detectors. showing a noise-equivalent power (NEP) of ∼10^−19 W/Hz^1/2 and an energy resolution of ∼500 GHz. Finally, the technologies nowadays in the R&D phase, such as
superconducting qubits are limited to single-photon detection and extremely prone to the external environment.
In this talk, i will present the scientific background and goals of the project QuLEAP funded by the MUR by a FIS2 Consolidator Grant. QuLEAP aims at developing a new cryogenic quantum detection platform pushing the detection sensitivity towards unprecedented levels. To this scope, the project will exploit innovative concepts for the charge and energy management in hybrid mesoscopic superconducting systems. First, the current control of critical temperature of fully superconducting Josephson junctions allows the Josephson escape sensor (JES) to show a record NEP ∼10^−25 W/Hz^1/2 and energy resolution of ∼2 GHz. Second, the macroscopic phase coherence of superconductors will be exploited to realize a nonlocal superconducting detector (NLSD) with separated sensing and readout elements, thus able to reveal single-photons of frequency down to ∼10 GHz. Third, the bipolar thermoelectric response of fully superconducting tunnel junction will be employed to attain single-photon detection in a wide range of frequencies ranging from 10 GHz to 10 PHz.
Concluding, the set of unprecedentedly sensitive detectors developed within QuLEAP operates in synergy with current detection, cold electronics and room-temperature readout technologies, thus enabling new functionalities and filling the existing gaps between the requirements of fundamental physics experiments and the present sensing technologies.
Recent particle physics experiments requiring excellent energy resolution involve cryogenic detector arrays composed of hundreds of detector pixels, such as Transition Edge Sensors (TESs). To preserve the intrinsically excellent energy resolution of these detector arrays while maintaining minimal system complexity, a broadband, multiplexed read-out chain, with minimal noise addition is required.
This goal can be achieved through the implementation of microwave multiplexing and quantum noise limited amplification, technologies that can be implemented exploiting the non-linearity of superconducting high-kinetic inductance circuits.
Microwave multiplexing of TESs can be realized with Kinetic Inductance Current Sensors (KICS), arrays of high-kinetic inductance resonators coupled to a common microwave feedline, whose resonance frequencies are modulated by the output signals of TESs coupled to them.
The resonance frequencies, and thereby the detector states, are probed with an adequate microwave frequency comb. The readout of the modulated frequency comb requires quantum noise limited amplification in order to maintain the excellent energy resolution. For this purpose Kinetic Inductance Traveling Wave Parametric Amplifiers (KI-TWPA) prove useful, achieving minimal noise addition for a broad range of frequencies, which is critical for the read out of a large number of detector pixels
In this contribution we will present our most recent results on the design, simulation, microfabrication and cryogenic characterization of KICSs and KI-TWPAs based on the high-kinetic inductance material NbTiN.
We present the design of a hybrid photon number-resolving detector (PNRD) on a lithium niobate-on-insulator (LNOI) platform, aiming to combine superconducting nanowire single-photon detectors (SNSPDs) in a multiplexed configuration for high-fidelity quantum sensing. Finite element method (FEM) simulations have been conducted to assess key performance factors such as propagation losses, detector dark counts, and waveguide geometry, providing a comprehensive framework for the device's development.
The proposed detector will integrate up to 130 SNSPDs along a thin-film lithium niobate waveguide, targeting photon number resolution for up to 20 photons with >90% efficiency. Simulations predict low propagation losses (0.3 dB/cm) and near-ideal absorption with optimized nanowire lengths. This modular architecture is designed to overcome challenges such as current crowding and bending losses while ensuring scalability and precision.
This platform represents a significant step toward fully integrated quantum sensing systems, with future applications in quantum metrology, state engineering, and continuous-variable quantum technologies.
Superconducting detectors are currently being developed, optimised and deployed for all forms of physics experiments due to their incredible performance that combines moderate-to-elevate energy resolution, time and spatial resolution with high quantum efficiency and effectively near-zero dark counts. At the Pisa section we are moving the first steps in detector design and fabrication, with the aim of building a fully operational facility in the coming years, to foster various R&D programs in the field of cryogenic detection for fundamental physics. Moreover, thanks to the engagement in experiments like LSPE and LiteBIRD we have developed a substantial experience in TES readout electronics and characterization.
We will present the work carried out at the Pisa section towards the scope of these experiments as well as an overview of our cryogenic, test readout and fabrication facilities.
In the last years, gravitational-wave (GW) Earth-based detectors have seen a great improvement in sensitivity, leading to the detection of more than 100 events during the joint observing runs of the LIGO-Virgo-KAGRA (LVK) Collaboration. This has opened the way to a completely new field of study, i.e. multimessenger astrophysics.
The contribution presented here is about taming quantum noise to further enhance the sensitivity of GW detectors, in view of next-generation detectors such as the Einstein Telescope.
Excluding technical noises, quantum noise dominates the high-frequency band (300 Hz - 10 kHz) and it will become limiting also in the other bands (10 - 300 Hz), with the expected improvements of other noise sources. Therefore, we are developing a table-top optical prototype to validate a novel technique for quantum noise reduction via Einstein-Podolsky-Rosen (EPR) entangled squeezed states of light. The quantum entanglement allows to attain a broadband noise reduction and it drastically simplifies the state-of-the-art optical setup needed to achieve similar performances, being also much cheaper.
The talk will give an overview of the current status of the experiment both in simulations and experimental design of the EPR project. This experiment is hosted by the EGO (European Gravitational Observatory, Cascina, PI) consortium and counts members from several INFN groups (Roma1, Napoli, Genova, Perugia) and from KASI (Korea Astronomy and Space Science Institute) and South Korean institutions.
Quantum noise is a fundamental limitation in gravitational wave detectors, restricting their sensitivity and scientific reach. To overcome this challenge, current detectors rely on frequency-dependent squeezing, implemented using long filter cavities to reduce quantum noise across a broad frequency range. While effective, this approach is difficult to scale, particularly for next-generation interferometer designs that would require additional hundred-meter-scale filter cavities. In this talk, I will present a new method for generating frequency-dependent squeezing using a hybrid quantum network. By coupling an atomic spin ensemble to an entangled light source, our approach enables broadband quantum noise suppression in the acoustic frequency range without the need for large filter cavities. This technique offers a compact and flexible alternative for future gravitational wave detectors and may also find applications in distributed quantum sensing and continuous-variable quantum communication.
Abstract for IFD 2025 - INFN Workshop on Future Detectors, on March 17-19, 2025
(https://agenda.infn.it/event/43956/abstracts/#submit-abstract)
Title: Entangled Squeezed Light for Quantum Noise Reduction in Small-Scale suspended Interferometers
Presentation type: SIPS
Authors: W. Ali¹ ² (On behalf of the EPR-SIPS team)
Affiliations:
¹ INFN Genova, ² University of Genova,
Abstract
Gravitational wave (GW) detectors are fundamentally limited by quantum noise, affecting sensitivity across their detection bandwidth (10–10,000 Hz). Quantum shot noise dominates at high frequencies, while quantum radiation-pressure noise limits performance at low frequencies. To overcome these constraints, modern interferometers utilize Frequency-Dependent Squeezing (FDS) with a detuned filter cavity (300m), reducing quantum noise dynamically. However, an alternative approach using Einstein-Podolsky-Rosen (EPR) entanglement offers a promising method for broadband noise suppression. The Suspended Interferometer for Ponderomotive Squeezing (SIPS) serves as a small-scale experimental platform to explore these noise reduction techniques. Designed with a Michelson configuration and high-finesse Fabry-Perot arm cavities, SIPS investigates ponderomotive squeezing, where quantum correlations are induced between the light field and suspended optics. SIPS will operate with a double-pendulum and monolithic suspension system made of fused silica fibers for reducing thermal noise and providing stable optical alignment. The high-precision local control system, based on PXI-based data acquisition and position-sensitive detectors (PSDs), continuously monitors angular (pitch, yaw) and linear (z-pendulum) displacements. Real-time feedback through LabVIEW-based control enables corrective actuation, achieving angular stability. The talk will give an overview of the SIPS status, from simulation and setup point of view.
Resistive Micromegas detectors have proven, over the years, to be a reliable detector technology. This presentation will report on further improvements and developments of such detectors for robust and stable operations. The ongoing project focuses on the optimisation of the design with small readout elements, employing pads, and of the spark protection system. Optimal layouts have reached high stability and good rate capability, up to tens MHz/cm$^2$. Spatial and time resolution of the order of 100$\mu$m and below 10ns, respectively, have been achieved and can be tuned depending on the application.
Notably, solutions with simplified layouts for medium and low rate applications, such as the muon systems of the FCC-ee detector concepts, are developed using the capacitive sharing technique. Key results will be presented, focusing in particular on recent measurements with radioactive sources and test-beam data analysis.
The novel G-RWELL Micro Pattern Gaseous Detector (MPGD) is a hybrid configuration that combines two technologies - Gas Electron Multiplier (GEM) and μ-RWELL - to achieve gas gains above $10^4$. This makes it a cutting-edge solution for high-precision tracking applications.
The higher gas gain is reached thanks to the inclusion of a single GEM layer for signal pre-amplification, and it enables the use of MPGDs for efficent 2D tracking, supporting a wide range of applications. This technology has been chosen for the ePIC Endcap Trackers to be developed for the Electron-Ion Collider (EIC) at Brookhaven National Laboratory. The Endcap Trackers consist of two pairs of G-RWELL disks, positioned in both the leptonic and the hadronic regions.
The design includes a drift gap of $3−6$ mm and a transfer gap of $2−3$ mm, while a 2D strip “COMPASS-like” readout with a $600$ μm pitch ensures a spatial resolution better than $150$ μm, even for curved tracks. This guarantees full compatibility with the operational requirements of the ePIC experiment.
This contribution highlights the innovative G-RWELL technology and its integration into the ePIC tracking system, demonstrating its potential to enhance detector performance in state-of-the-art nuclear physics experiments. Results from a recent test beam campaign (conducted in November 2024 at the PS-T10 East Area at CERN) have been obtained on the spatial resolution and detection efficiency. Prototypes of 10x10 cm$^2$ were tested for varying angles of incidence between the beam and the detector surface, prooving the high quality of this novel technology performances. The design of full scale quadrants of 50 cm radius are being designed.
AMBER (NA66) is a fixed-target experiment at M2 beam line of the SPS, devoted to various fundamental QCD measurements. For this new apparatus we are designing together with the CERN MPT workshop both a ~1.2x0.5 $m^2$ bulk resistive MICRO-MEsh GAseous Structure (Micromegas) detector and a new custom 64 channel fully digital front-end ASIC ToRA (Torino Readout for AMBER) for timing and energy measurements. The ASIC is closely tailored to the specifications of the Micromegas but also should be fully suited to equip some of the existing Wire type detectors to make them compatible with the future trigger-less Data AcQuisition system (DAQ) of AMBER. This simultaneous design of the ToRA ASIC and of the associated detector should allow for a good optimisation of their common performance. The challenge is coming from the resistive Micromegas with 1.0 -2.5 fC signals at the low end of the charge amplitudes together with ~1.2 m long strips of up to ~550 pF capacitance reaching hit rates of 500 kHz/strip. To face these conditions, we need a good control over the system noise and signal integrity performance of the detector itself together with the full signal path to the ASIC and proper ASICs integration. The first full size prototype of the detector has been delivered in October of 2024 while the ToRA _v1 ASIC is in its final design phase. We will briefly present the first test results of the detector together with the current ASIC concept and integration challenges.
The Imaging X-ray Polarimetry Explorer (IXPE) represents the current state-of-the-art of astrophysical X-ray polarimetry. This mission (collaboration NASA and ASI) has been launched on December 9th 2021 and it can measure the linear polarization of different astrophysical sources over the photon energy range 2-8 keV. The core of IXPE Detector Unit and future X-ray polarimetry missions is the Gas Pixel Detector (GPD). The X-ray photons enter the detector volume through a Beryllium window and are absorbed into the dimethyl-ether gas, interacting via photoelectric effect. In the gas gap, an electric field drifts the primary ionization electrons towards the Gas Electron Multiplier and the produced charge is collected on the readout ASIC.
GPDs can be calibrated and characterized using the X-ray Calibration Facility (XCF), available at the Physics Department at the University of Turin. The XCF is a table-top, open-design irradiation setup for research: it offers beams of photons at different energies and with different spatial and polarization configurations. The radiation source can be chosen between a single-anode and a multi-anode X-ray tube. In addition, the XCF can provide two beam-lines: one of them is linearly polarized through Bragg diffraction on a number of crystals that are selected to fulfill the Bragg condition at the primary beam energy.
Thanks to a handling system, the GPD can measure both the unpolarized and polarized beam: for example, in the first case, spurious effects that take place in the detector and the intrinsic polarization of the source can be studied, while, in the second, the GPD response to the polarized radiation can be characterized. In addition, to study long-term variations of the GPD response, it is possible to use a 55 Fe radiative source.
Initially conceived as a calibration source to qualify GPDs, the XCF can satisfy evolving requirements to support R&D programs of innovative position-energy and polarization-sensitive X-ray detectors.
Gas Electron Multipliers (GEMs) are crucial for high-resolution X-ray polarimetry, enabling precise measurements in astrophysical missions like IXPE, Polarlight, and the upcoming eXTP telescope. While the IXPE collaboration has refined Gas Pixel Detector (GPD) technology using conventional GEM fabrication methods such as wet-etching and laser drilling, further optimization of hole patterning remains essential. Achieving ideal aspect ratios and minimizing dielectric charging are key to ensuring gain stability and detector uniformity. This work investigates a plasma-based Reactive Ion Etching (RIE) technique at FBK to address these challenges, producing GEMs with more vertical and uniform hole profiles. We introduce a plasma-based GEM geometry with 30 μm diameter holes and a 50 μm pitch, characterized by SEM and PFIB analysis. Collaboration with INFN Pisa and Turin enabled extensive electrical testing and performance validation in GPDs, supported by Garfield++ simulations. Initial results show that plasma-etched GEMs exhibit gain vs. voltage behavior comparable to IXPE currently deployed detectors. While still in early R&D, this fabrication approach holds significant potential to enhance the sensitivity of future space-based X-ray polarimeters, improving measurement accuracy and advancing detector technology. Future work will focus on quantitatively evaluating the performance of plasma-based GEMs relative to conventional ones, particularly in terms of X-ray polarimetry resolution in the keV range.
We present the design, development, and initial performance of a large-volume, wide field-of-view Time Projection Chamber (TPC) tailored for X-ray polarimetry. The instrument employs a triple-GEM detector with an optical readout system, using a scientific CMOS (sCMOS) camera to capture the secondary scintillation light produced during gas amplification. Initially optimized for directional Dark Matter searches, this system has been successfully adapted to measure the polarization of X-rays, opening a new observational window into the high-energy universe.
X-ray polarimetry provides critical insights into the magnetic fields, geometries, and emission mechanisms of cosmic sources such as black holes, neutron stars, and supernova remnants by complementing traditional intensity and energy measurements with polarization data. The prototype TPC features a cylindrical active volume (radius 3.7 cm, height 5 cm) and was tested at the INAF-IAPS calibration facility in Rome, Tor Vergata. Tests suggested complete reconstruction of photoelectron tracks in the 10–60 keV range, with angular resolutions down to 15° and energy resolutions between 10–15% over the 5–45 keV range. Analysis of electron tracks obtained using a collimated ⁹⁰Sr source showed angular resolutions better than 30° for energies above 10 keV and below 20° for energies between 20 and 60 keV, with possible modulation factors reaching up 0.6 and 0.8, respectively. Preliminary results from the first calibration using a fully polarized 17 keV X-ray beam at the INAF facility are promising. They suggest a modulation factor greater than 0.4 can be achieved at this energy.
This innovative TPC design not only extends the energy sensitivity of X-ray polarimetry but also enhances the capability to observe rapid transient phenomena, such as Gamma Ray Bursts and solar flares. Future developments will explore alternative gas mixtures to optimize the photoelectric cross-section, with planned experiments using fully polarized X-ray beams at the INAF calibration facility.
The identification and discrimination of electronic and nuclear recoil events at low energy thresholds are significant challenges in contemporary dark matter direct detection experiments. Gaseous Time Projection Chambers (TPCs) with optical readout offer a promising and innovative solution in this context. As a result of the high granularity and sensitivity of advanced scientific CMOS (sCMOS) light sensors, this technique provides excellent energy and 3D position reconstruction capabilities. The CYGNO collaboration is pursuing this approach by developing a gaseous TPC that operates with a gas mixture of He and CF$_4$ at atmospheric pressure, equipped with a Gas Electron Multiplier (GEM) amplification stage. An event induced in such a detector results in the production of visible light, which is collected by sCMOS cameras and a set of fast photosensors. Recently, the 50 L LIME prototype was operated underground at the Laboratori Nazionali del Gran Sasso (LNGS) to evaluate the performance of the CYGNO methodology in a low-background environment and to refine the trigger and data acquisition systems for the future upgrades. This experience is a critical step towards the currently ongoing commissioning of CYGNO-04, a larger 0.4 m$^3$ demonstrator of the CYGNO experiment.
The MEGII experiment at the Paul Scherrer Institute (PSI) has set the best upper limit in the world on the branching ratio of the Charged Lepton Flavor Violating (CLFV) decay $\mu^+ \rightarrow e^+ \gamma$, equal to $\mathcal{B}(\mu^{+} \rightarrow e^+ \gamma)<3.1\times 10^{-13} \text{ (90% confidence level)}$. If this decay is observed experimentally it would indicate evidence of New Physics (NP) beyond the Standard Model (SM), while limits on its $\mathcal{B}$ will constrain NP models' parameters.
To improve the results of MEGII, which aims to reach a sensitivity of $6 \times 10^{-14}$ by collecting data until 2026, efforts are ongoing at PSI and elsewhere to increase the muon beam intensity up to $\mathcal{O}(10^{10})\mu$/s. In such high-rate environments, the detector components must be upgraded accordingly. A convenient method for reconstructing the photon could be to convert it into an $e^+e^-$ pair and track the emitted leptons to measure the $\gamma$ energy and direction.
Currently, a radial Time Projection Chamber (TPC) with a drift length of $\sim$10cm, a Resistive Micro-Wells ($\mu$RWells) amplification stage and orthogonal strips readout is under study, satisfying the requirements of a light and compact tracker for the $e^+e^-$ pairs. The $\mu$RWells are micro pattern gaseous detectors, characterized by a resistive layer between the amplification and the readout regions, which allows to reach high rates without the formation of permanent discharges.
This kind of detector is also being considered by the n_TOF collaboration, which is working on an experiment that aims to probe the existence of a new boson, named X17, that could explain the anomalies observed for the first time at the ATOMKI laboratory (Hungary). Four TPCs with $\mu$RWells and strips readout will be used to track the $e^+e^-$ ejected from the performed nuclear reactions.
A prototype detector with a drift length of 3cm was characterized in a test beam at ATOMKI in May 2024, showing a position resolution of $\sim 800\mu$m and an angular resolution of $\sim 2$°. Some construction criticalities of the considered device have been addressed, and potential ideas have been suggested to improve the design and the data analysis. Further studies are ongoing and tests of improved prototypes are in program.
Among future collider proposals, the Muon Collider stands out for its unique potential in advancing energy frontier research. However, a major challenge arises from Beam-Induced Background (BIB), caused by muon decay along the beam pipe, which complicates detector design and event reconstruction. Despite the use of tungsten conical absorbers (nozzles) in the forward regions, an irreducible component of BIB reaches the detector, characterized by low-momentum particles and delayed arrival relative to the bunch crossing. The BIB flux on the barrel inner face of the electromagnetic calorimeter reaches approximately 300 particles per cm$^2$, with a total ionizing dose of ~1 kGy/year and a neutron fluence of 10$^{14}$ n$_{1\, MeVeq}$ cm$^{-2}$ per year.
To address these challenges, innovative mitigation strategies are essential. One promising approach is CRILIN (CRystal calorImeter with Longitudinal INformation), a semi-homogeneous electromagnetic calorimeter employing Lead Fluoride (PbF₂) crystals read by UV-extended Silicon Photomultipliers. Designed with high granularity, longitudinal segmentation, and excellent timing capabilities, CRILIN has the potential to significantly reduce BIB effects while achieving high energy resolution (< 10 %/$\sqrt{E}$). This talk will present simulation results evaluating CRILIN’s performance, along with recent experimental findings from prototype tests, highlighting its potential in the challenging Muon Collider environment.
Relativistic particles passing through crystalline structures experience a Lorentz-boosted external electric field. For high-Z crystals, if the impinging angle relative to a lattice axis is up one degree, the strong field (SF) felt by electrons and photons at an order of few GeV or higher can overcome the Schwinger limit, where the QED effects become nonlinear, and enhance the standard Bremsstrahlung and pair-production cross-sections described by the Bethe-Heitler model which applies to amorphous materials.
The SF-induced enhancement accelerates the formation of the electromagnetic shower and the ORiEnted calOrimeter (OREO) team, exploited this effect to develop an innovative homogeneous electromagnetic crystal calorimeter based on oriented scintillator crystals. This new type of calorimeter has higher energy resolution, improved photon detection efficiency, and higher particle identification due to the relative enhancement of electromagnetic interactions over hadronic ones. OREO is developed within subtask 1.3.4 of the DRD6 collaboration.
This contribution summarizes the results of the ongoing OREO R&D, from the realization of the first 3x3 prototype with oriented PWO crystals and its first tests on beam. We will also present the potential applications of this technology, including future accelerators, fixed-target experiments, and satellite-based γ-ray observatories.
The POKER (POsitron resonant annihilation into dark mattER) project aims to perform a missing-energy measurement employing a $\sim$100~GeV positron beam impinging on an active thick target. The beam interaction with this detector could produce feebly interacting massive particles, exiting from it undetected and carrying away a significant fraction of the primary positron energy. The crucial element of the POKER project is a high-resolution electromagnetic calorimeter used as the target, composed of lead tungstate crystals with a silicon photomultiplier-based readout system.
In this context, the POKERINO detector is a prototype for this new high-resolution electromagnetic calorimeter that served as a test bench to validate the POKER project's technical choices. It consists of a 3x3 matrix of PbWO$_4$ crystals, each with dimensions 2x2x22~cm$^3$ read by four SiPMs. The POKERINO response to high-energy particles was measured at the H6 beamline of the Super Proton Synchrotron (SPS) at CERN in 2024. This facility provides electron, positron, muon or hadron beams with energies ranging from 10~GeV to over 100~GeV, allowing testing POKERINO with various particle types over a wide energy range. In my contribution, I will present the POKERINO energy-resolution and linearity studies achieved through the test beam at CERN, highlighting how this analysis influenced the design of the detector. I will also report the latest achievements in the final POKER calorimeter R$\&$D effort, whose construction and preliminary characterization with cosmic rays were completed in Genova in early 2025.
Calorimeters at future Higgs factories will require excellent energy resolutions to discriminate W and Z boson hadronic decays. The Particle Flow Algorithm (PFA), which integrates data from various subsystems, is well-suited for this task. This contribution presents the development of a hadronic calorimeter made of resistive Micro Pattern Gas Detectors (MPGD) designed for experiments at future circular collider facilities, optimized for a Particle Flow approach. In this context, a muti-TeV Muon Collider is being explored as a key use case.
Allowing for a high-granular readout (O(cm$²$)), MPGDs are ideal as active layers in a sampling hadronic calorimeter for PFA. Additionally, these technologies are particularly suitable for the Muon Collider background conditions, as they are radiation-hard and capable of sustaining high rates (up to 10 MHz/cm$²$). Furthermore, resistive MPGDs, such as resistive Micromegas and µ-RWELLs, provide excellent spatial resolution, operational stability (discharge quenching), and uniformity, making them highly effective for calorimetry.
This contribution presents studies on energy resolution and timing conducted through standalone Geant4 simulations and the full Muon Collider simulations framework. Additionally, we report on characterization studies conducted with muon beams at CERN SPS on resistive MicroMegas and µ-RWELLs. We evaluate their efficiency, response uniformity, and space and timing resolution. Furthermore, we present the energy response of an HCAL cell prototype consisting of eight layers (~1 λ) of alternating stainless steel and MPGD detectors tested with pion beams of energy up to 10 GeV.
The IDEA apparatus, a proposed experiment for the future FCCee accelerator, recently incorporated a novel electromagnetic calorimeter into its baseline design. This calorimeter aims at improving the energy reconstruction for neutral particles to 3 % at 1 GeV, while simultaneously enabling particle-flow algorithms through fine segmentation.
Designed to fit inside the magnet coil, the crystal calorimeter will be composed of two scintillating crystal layers with approximate thicknesses of 6 X0 and 18 X0 . The required transverse cell size of 1-1.5cm, requires SiPM-based readout. It will complement the sampling hadronic calorimeter located outside the magnet and it will include a simultaneous measurement of Cherenkov fraction in the shower for the back layer, to maintain the double-readout capabilities of the whole calorimeter system.
INFN, in collaboration with the Calvision consortium in the USA, is actively involved in the proof of principle of such calorimeter with the sections of Milano Bicocca, Napoli and Perugia.
This contribution presents some results from the 2024 test beam, where PWO, BGO and BSO crystals were exposed to a 10-100 GeV electron beam at CERN H6 beamline. The primary objective was to demonstrate the double readout technique using SiPMs.
The single crystal under test was mounted on a rotation stage to exploit the directionality of the Cherenkov photons; we explored both optical and waveform template techniques for the identification, finally proving we can separate them from the scintillation.
A larger prototype, capable of shower containment is currently under development within the MAXICC prin project as part of the DRD6 collaboration and will be tested in beam in the fall.
Dual-readout (DR) calorimetry is one of the technologies of interest for the next generation of leptonic colliders such as FCC-ee. This calorimeter uses both scintillation and Cherenkov signals to correct for electromagnetic fraction fluctuations in hadronic showers, significantly improving the accuracy of energy measurement. Several prototypes and beam-test campaigns were conducted to validate its feasibility and to optimise design choices. The HiDRa (Highly Granular Dual-Readout Calorimeter) demonstrator represents an important step toward a modular, cost-effective and high-performance solution designed to comply with the 4-$\pi$ geometry required at collider experiments.
In 2024, half of the demonstrator (36/80 minimodules) was qualified for the first time with electron beams at CERN SPS, showing a good linearity response and energy resolution in accordance with Monte Carlo simulations. This talk will summarise the results of the latest beam tests.
The Deep Underground Neutrino Experiment (DUNE) is a next-generation neutrino oscillation long-baseline experiment designed to measure the neutrino mass ordering, the CP-violating phase in the lepton sector of the Standard Model and to improve the precision on key parameters that govern neutrino oscillations. The System for on-Axis Neutrino Detection (SAND) at the DUNE Near Detector complex is designed to monitor the beam on-axis, control systematics uncertainties for the oscillation analysis, precisely measure neutrino cross-sections, and perform short-baseline neutrino physics studies. SAND will exploit the existing KLOE electromagnetic calorimeter (ECAL) that will work with a $0.6$ T superconducting magnet, a 1-ton liquid Argon detector (GRAIN), and a modular, low-density straw tube target tracker system.
The ECAL is based on a lead-scintillating fiber sampling technology and consists of a cylindrical barrel composed of $24$ modules and two endcaps with $32$ modules each, providing nearly complete hermetic coverage of the SAND inner volume. Modules are $23$ cm ($\sim 15~X_0$) thick and are read-out on both sides by photomultiplier tubes (PMTs) with a granularity of $\sim 4.4 \times 4.4~cm^2$, for a total of $4880$ PMTs. Thanks to the excellent energy $\sigma_{E} / E \sim 5.7 \% /\sqrt(E)$ and time resolution $ \sim 54 ps /\sqrt(E(GeV))$ achieved in KLOE, precise reconstruction of electromagnetic showers and high performance in particle discrimination have been reached. Leveraging these technological characteristics, the SAND ECAL will enhance event reconstruction, improve neutrino interaction vertex determination, and contribute to background rejection. In this talk, the current configuration of the ECAL, the reconstruction algorithm and the particle discrimination performance for SAND will be presented.
The ROSSINI project (Remotely-operated On-board Inspections for Special Nuclear Material) is designed to revolutionize the detection of illicit Special Nuclear Material (SNM) in cargo containers by integrating advanced aerial and ground-based robotic systems.
This innovative approach leverages radiation-sensitive detectors mounted on remotely operated drones and terrestrial robots to conduct preliminary inspections while vessels are still approaching the port. Upon docking, suspicious containers are subjected to additional external verification using robotic detection units before being unloaded. If anomalies are detected, a detailed internal inspection follows to confirm the presence of illicit material.
To enhance operational efficiency and security, the system is integrated with the RAISE network, providing real-time monitoring, automated alerts, and coordinated response planning. By minimizing the need for direct human intervention, ROSSINI significantly reduces radiation exposure, optimizes inspection times, and strengthens nuclear security protocols.
The DIANA (Development of a sustaInable Amorphous Novel scintillAtor) project aims to develop a novel hybrid scintillator that combines the advantages of organic and inorganic scintillators by leveraging scintillating crystal fragments. This dense, optically continuous material will be scalable to large dimensions, easily machinable into desired shapes, and economically competitive. The crystal fragments, sourced from production residues or damaged scintillators, will be embedded in an amorphous matrix of glass or polymer.
This hybrid scintillator will enable the construction of detectors with diverse applications, such as high-energy physics experiments and veto systems, offering economic benefits and promoting the reuse of materials. The amorphous matrix will be tailored to achieve the required density and optical properties, ensuring efficient optical coupling with the scintillating fragments.
Polymer-based matrices will be produced at room temperature by mixing the fragments with liquid resins prior to polymerization. Glass-based matrices will be fabricated by heating a mixture of glass and fragments to sintering temperatures, resulting in an optically and mechanically continuous material after cooling.
Over the project's two-year span, the optimal methodology for producing homogeneous, defect-free samples will be refined. Prototypes will be characterized in terms of scintillation performance, light attenuation, and radiation hardness, including dedicated beam tests.
Ultimately, the DIANA project aims to deliver a scintillator with high performance and competitive costs while advancing eco-friendly technologies. The reuse of crystal fragments addresses the limited industrial recycling options currently available, as repeated processing often degrades their optical properties.
Plastic scintillators primarily consist of a fluorophore—which absorbs and converts the kinetic energy of particles into lower-energy light—dissolved in a polymer matrix, with the frequent addition of a wavelength shifter. Despite the numerous advantages offered by plastic scintillators, including fast scintillation signal, low cost and ease of manipulation and shaping, they are characterized by a low atomic number Z, which negatively affects their ability to detect the photopeak of gamma rays. Attempts at solving this issue have been made by loading the plastic scintillators with high-Z impurities to increase their effective Z. However, the fabrication of samples exhibiting high transparency, homogeneous dopant distribution and light output comparable to that of inorganic crystals is challenging. Not even the leading companies specializing in the fabrication of organic scintillators offer samples exceeding 5% dopant concentration, due to the associated degradation in optical clarity and scintillation efficiency. These limitations prevent applications in nuclear medical imaging, where the ability to detect the gamma-ray photopeaks is crucial to guarantee the required diagnostic efficiency.
Our research line aims at developing loaded plastic scintillators to realize medical imaging detectors that are expected to offer improved time performances at a lower cost, thus broadening the availability of these crucial tools in the fight against cancer. In particular, two projects are ongoing. The first one (reSPECT project) concerns the implementation of a new SPECT (Single-Photon Emission Computed Tomography) detector based on our high-Z doped scintillators polymerized inside the holes of a 3D-printed tungsten collimator, read by CMOS sensors arranged in tiles. The second one (TRONDHEIM project) aims at realizing a compact portable dosimeter for radiopharmaceutical dose customization in 177-Lu-PSMA-617 radio-metabolic therapy.
The first step we accomplished was the synthesis of a new series of organic molecules to serve as fluorophores in the plastic scintillators [Patent: Mattiello L.; Patera V.; Belardini A.; Rocco D.; Marafini M.; Organic Scintillator. Patent WO2023156957A1, 2023]. Through the comparison of light output and time properties of these novel materials [D.Rocco et al., “TOPS fast timing plastic scintillators: Time and light output performances”. NIM A 1052, 168277 (2023); doi: 10.1016/j.nima.2023.168277], we identified the most promising candidates, subsequently employed in the realization of scintillator prototypes enriched with Bismuth in concentrations up to 10%. The results are encouraging in terms of transparency, homogeneity and performances of the final samples.
Moreover we explored different manufacturing techniques, from the polymerization of the PVT-based loaded scintillators inside various molds (PE, PTFE, metal) to the use of 3D-printed resin as scintillator substrate.
Most future projects for hadronic calorimeters involve the use of multi-channel photodetectors (SiPMs) to achieve high readout granularity, allowing for improved jet resolution and better access to the substructure of overlapping jets.
Reading out each individual channel, especially for large calorimeters, would result in an uncontrollable and prohibitive increase in the number of channels to be digitized.
A new versatile high-bandwidth analog device that can amplify and sum individual photodetector channels in a fully configurable manner could be used to mitigate the problem. Such a device offers the advantage of fully configurable readout granularity that can be adjusted based on the type of process being analyzed or different calorimeter regions.
The feature that differentiates the device from similar ones available on the market is its ability to perform programmable analog sums of any channel subset. This allows for selection of readout regions of interest of the analog signal pattern before digital conversion.
A first prototype of this device, developed with high-bandwidth IC, has been designed and tested at INFN Pisa. The prototype is capable of generating the analog sum of up to 64 input signals. Input signal equalization or weighting can be achieved through a programmable gain before the analog sum. Additionally, the output signal can be amplified to fit the dynamic range of any external digitizer. The complete device configuration is done through a custom GUI.
The prototype tests provide excellent results in terms of pulse shape stability, time jitter, and linearity of the analog sum of an arbitrary number of channels.
A 64-channel ASIC version of this device, suitable for both research and industrial applications, is currently under development.
The PHeSCAMI project (Pressurized Helium Scintillating Calorimeter for AntiMatter Identification) aims to identify anti-deuterium in cosmic rays by exploiting the existence of delayed annihilations (~μs) expected in a pressurized helium target. The technique relies on measuring the helium scintillation signal (80 nm), which requires a two-stage WLS (Wavelength Shifter) conversion. This contribution presents test measurements of the second-stage WLS, based on the FB118 material produced by ""Glass to Power"".
The absence of residual scintillation and the high efficiency of UV photon conversion in FB118 suggest its potential application as a compact Cherenkov detector in CubeSats, enabling particle velocity measurements in the range of 0.75c to 0.95c.
In commonly used liquid Argon time projection chambers, charged particle tracks are reconstructed with a good spatial resolution employing the charge signal, while the scintillation light signal is used only for determining the interaction time or for calorimetry. However, LAr scintillation yield is very high, and the possibility to fully exploit the scintillation signal was considered to heavily enhance the time resolution of the detected events while keeping the high position resolution.
An innovative liquid Argon optical detector is under development for imaging charged particle tracks emitted from neutrino interaction events inside GRAIN, the liquid Argon target of SAND in the DUNE Near Detector Complex.
Thanks to the innovative UV cameras, fast scintillation light in LAr can be focused by a proper optical system into a high granularity 32x32 Silicon Photo-Multiplier (SiPM) matrix with SiPMs of 2 mm side. One possibility for the optical systems is based on a UV cryogenics lens. The lens design is optimized for focusing tracks crossing a volume between 40 and 100 cm from the lens plane, and the first UV camera prototype with a 16x16 SiPM matrix has been built and is under testing in the ARTIC facility at the University of Genova.
In this talk, the preliminary design of the lens-based optical detector will be discussed, and the first results achieved with the prototypes will be shown, together with the expected performances of neutrino event reconstruction in GRAIN.
Large volumes of liquid Argon or Xenon constitute an excellent medium for the detection of neutrino interactions and for Dark Matter searches.
Imaging of scintillation light can provide vertexing and tracking information on its own and, when combined with other detection methods, enhances resolution and improves event reconstruction in high-rate environments.
Both Xenon and Argon scintillate in the VUV range, imposing strict requirements on the optical system and SiPMs. A compact camera with both a deep and wide field of view can be achieved using a coded aperture mask.
This presentation describes this imaging system and its reconstruction algorithm using Maximum Likelihood Expectation-Maximization, aimed at providing a three-dimensional map of the energy deposited by charged particles. This approach presents a significant computational challenge, as it requires a GPU optimized implementation.
Advancements in 3D interconnecting technologies have significantly contributed to the emergence of a new generation of Silicon Photomultipliers (SiPM), which we can refer to as hybrid devices. These devices integrate the functionalities of digital SiPMs with the exceptional performance characteristics of specialized custom technologies. In recent years, the Fondazione Bruno Kessler (FBK) has been working on the technological development of Backside Illuminated (BSI) SiPMs for Vacuum Ultraviolet (VUV) and Near Ultraviolet (NUV) light detection, particularly in applications in particle physics experiments, such as detection of scintillation from liquefied noble gases.
For this wavelength range, a BSI detection technology faces critical challenges due to silicon's low photon interaction depth (less than 100 nm for λ = 400 nm). This necessitates the complete removal of the substrate, a process that has already been successfully demonstrated at FBK and the creation of a thin active “entrance window”. Additionally, for VUV-sensitive devices, the glass carrier wafer must be removed from the entrance window, as it typically absorbs light for wavelengths shorter than 350 nm. We will present the latest progress in the microfabrication technology of BSI-SiPMs and the results from the first batch, produced in the framework of the INFN IBIS project.
DarkSide-20k is a background-free experiment under construction at INFN, Laboratori Nazionali del Gran Sasso, whose purpose is to directly detect Dark Matter particles exploiting WIMP-nucleon scattering in liquid Argon and an innovative active veto, which takes advantage of liquid Argon scintillation, to identify background neutron interactions. The construction specifications of the experiment are evaluated during the design phase through Monte Carlo simulations; however, simulating the transport of particles in large volumes is time-consuming, and the efficiency of these simulations is low, given the shielding materials the geometry comprises. Specifically, simulating neutrons originating from the underground hall where DarkSide-20k is installed requires a significant amount of computational resources. For this reason, Monte Carlo biasing techniques based on geometrical importance sampling have been implemented, to both enhance the accuracy of such simulations and reduce their run time. The conducted studies show that, with a suitable choice of the simulation parameters, it is possible to reduce the statistical error on the background event counts by a factor 15, achieving the same precision as standard Monte Carlo simulations while simulating a factor 500 less particles
DUNE is a next-generation, long-baseline neutrino oscillation experiment. The System for on-Axis Neutrino Detection (SAND) is one of the three Near Detector components, permanently located on-axis. Its primary goals are to monitor the beam and to measure the neutrino flux, along with a broader physics program including precision measurements of neutrino cross-sections. This will be possible thanks to an inner liquid Argon volume and a modular, low-density target/tracker system which allows precise control over the chemical composition and mass of the (anti)neutrino targets. In this talk, the tracker performance to detect neutrino events on solid Hydrogen, its design, and its reconstruction algorithm based on an Extended Kalman Filter will be presented.
The precise characterization of photomultiplier tubes (PMTs) is critical for the advancement of next-generation neutrino detection experiments. At the CAPACITY laboratory, we have developed dedicated measurement setups to investigate the quantum efficiency (QE) and performance of PMTs with diameters of up to 20 inches. Our system enables radial and surface scans of the photocathode with three translational and two angular degrees of freedom, allowing for high-resolution QE mapping and controlled variation of the incident light angle.
These measurements are conducted across the ultraviolet (UV) to near-infrared (NIR) spectral range, utilizing both continuous light sources and picosecond pulsed lasers at six distinct wavelengths.
In addition to QE characterization, we have conducted systematic studies on the effects of intense light exposure and elevated temperatures on photocathode degradation. The temporal evolution of QE post-exposure is analyzed to assess long-term stability. Furthermore, we employ an absorption spectroscopy setup to monitor, in real time, the diffusion of cesium within the PMT glass bulb—an essential process linked to photocathode degradation.
For large-scale performance evaluation, we use a dedicated dark box to test up to 62 PMTs simultaneously. Each PMT is equipped with the digital base developed for the KM3NeT experiment. In this setup, time-over-threshold (TOT) signals, generated by laser illumination of the PMTs, enable precise assessment of timing resolution and dark noise characteristics. This work plays a key role in completing the KM3NeT neutrino telescope and optimizing the performance of its detection units for deep-sea neutrino observations.
Future new high luminosity colliders will require exeptionally radiation hard detectors, in particular those that will be closer to the interaction regions, i.e. tracking and vertexing detectors. The TimeSPOT R&D project has developed a new family of 3D silicon pixel sensors with 55 μm pitch that have shown an outstanding time resolution of about 10 ps thanks to their new “trench” design. In these detectors, specially designed vertical (3D) trench junctions within the pixel create a uniform electric field region 25 μm thick, independent of the sensor’s thickness, allowing to collect charge carriers created by a crossing charged particle very rapidly. Such geometry minimizes charge carrier losses occurring in radiation damaged detectors and it has been demonstrated that these 3D detectors can still operate efficiently after neutron irradiations up to fluences of 1E+17 1MeVneq/cm2. A new irradiation run at the TRIGA Mark II Reactor at the Jožef Stefan Institute has just been concluded, reaching extreme fluences of 1E+18 1MeVneq/cm2. Irradiated 3D pixels have been tested at INFN Cagliari laboratories with red and infrared micrometrically focused laser beams allowing to perform a complete
mapping of the charge collection efficiency on the pixel area. Such
results will be presented at the workshop, showing that these 3D silicon pixels can still operate efficiently under extreme radiation damage conditions.
The Belle II experiment at SuperKEKB operates at a record luminosity of $5.1 \times 10^{34}~\mathrm{cm}^{-2}~\mathrm{s}^{-1}$, with plans to reach $6 \times 10^{35}~\mathrm{cm}^{-2}~\mathrm{s}^{-1}$. To handle higher backgrounds and improve tracking precision, an upgraded vertex detector (VTX) is needed. The new VTX will feature 5-6 layers equipped with OBELIX, a depleted monolithic active pixel sensor designed for high space-time granularity, low material budget ($<3\%~X_0$), and robustness to machine-induced backgrounds.
Based on Tower 180 nm technology and derived from the TJ-Monopix2 sensor (originally for ATLAS), it offers a $33~\mu\mathrm{m}$ pitch, precise time stamping, and, thanks to its new digital periphery, supports Belle II's 30 kHz trigger rate, handling hit rates up to $120~\mathrm{MHz}/\mathrm{cm}^2$.
Extensive laboratory and beam testing of TJ-Monopix2, including irradiated samples (NIEL up to $5 \times 10^{14}~\mathrm{n}_{\mathrm{eq}}/\mathrm{cm}^2$ and TID up to 100~Mrad), highlight its strong post-irradiation performance under various conditions.
These results not only optimise OBELIX's design for Belle II's challenging background conditions, but also demonstrate its potential for future high-energy physics experiments in extreme environments, such as FCC-ee.
Monolithic CMOS silicon sensors represent an important innovation for high-energy physics experiments due to their cheaper production and assembly cost compared to hybrid ones, where the electronics and the sensor are produced on different silicon substrates and later connected using bonding techniques. However, concerning the time resolution, today the most mature and high-performance technology is represented by the Low Gain Avalanche Diode (LGAD), an hybrid solution of a silicon sensor with an internal gain.
The last ARCADIA submission exploited the integration of the LGAD concept in CMOS Monolithic Active Pixel Sensors (MAPS) to obtain the benefits provided by both technologies. The multiplication of the signals in MAPS has a major impact on the signal-to-noise ratio; hence, the power consumption of the in-pixel front-end can be lowered to achieve the same performances. One of the possible applications of this innovative sensor is the Time-Of-Flight (TOF) system for a next generation heavy-ion experiment in high-energy physics, named ALICE 3 at the LHC. Moreover, this technology presents attractiveness for space applications where low power absorption is desired. Nevertheless, the union of the two technologies still lies in its early stages, and vigorous R&D is necessary.
This presentation will focus on the latest characterization results on these structures with internal gain fabricated in a standard 110 nm CMOS technology. An overview of these sensors will be provided, with emphasis on laboratory measurements and comparisons of experimental data with simulated ones. Promising results obtained from the analysis of the data collected during the latest test beam at CERN PS will be also shown. Finally, the future perspectives and an insight into the ongoing R&D will be given.
The ATLAS Experiment is building a complete new Silicon tracker, so called ITk, to face the challenges imposed by the HL-LHC phase in terms of instantaneous and integrated luminosity. The tracker will have pixel detectors in the innermost part and strip detectors in the outermost part. To deal with the high fluence, the innermost layer of the pixel detector will be instrumented by 3D sensors, that are extremely radiation hard, while the rest of the layers will host planar sensors.
The 3D sensors are produced by two vendors, SINTEF (Norway) and FBK (Italy) in two pixel pitches. In fact, to optimize the tracking performance, it is foreseen to use 50x50 um2 squared pixel in the forward region and 25x100 um2 rectangular pixel in the barrel section. In total there are three different sensors flavours: squared and rectangular from FBK and squared from SINTEF.
In this talk, we will review the laboratory measurements done to characterize the 3D sensors flavours. In particular, we will focus on the cross-talk between pixels, threshold and noise stability, and the evaluation of the active area of the edge pixels. Measurements are generally done as a function of the threshold and bias voltage, to better compare with the design expectations.
The INFN ARCADIA collaboration developed a fully depleted MAPS sensor as technology demonstrator aimed at next-generation experiments and applications in both e the space and medical field. Realized in LFoundry 110nm technology node, the ARCADIA sensor embeds a custom backside process to extend the depleted volume to the entire high-resistivity substrate, down to nanometers from the back surface, while maintaining a very good field uniformity and termination smoothness.
The fully depleted volume, with an overall thickness up to 200 um (but thinner substrates have been implemented as well) makes it suitable for low-energy X-ray detection, as well as near-UV imaging thanks to the very shallow insensitive layer at the back. The readout architecture, capable to handle a rate up to 100 MHz cm2, has been optimized for low power consumption, including a “space mode” for very low power operations.
Characterization has been carried out with table-top setup (radioactive sources and x-ray machine) and at test beam with Minimum Ionizing Particles, with a custom-made three layers telescope. Results on sensor performance and tracking resolution are discussed, together with possible applications and future developments.
Silicon microstrip (Si-µstrip) sensors are employed in most of current space detector tracking systems for charged cosmic-rays, such as the DAMPE satellite detector or the AMS-02 detector onboard the ISS. As they allow for large-area coverage with contained electronic channels and power consumptions, they are ideal sensors for high-energy physics applications in space-borne instrumentation, and are planned to be instrumented in envisioned follow-up cosmic-ray space-borne missions such as the AMS-100 or the ALADInO next-generation magnetic spectrometers.
The efficiency of such systems is however already currently impacted by "backsplash" particles generated from downstream calorimeters, which can degrade tracking efficiency by tens of percent, especially at energies approaching 1 TeV.
One potential solution to overcome this limitation and enable new measurement approaches in next-generation instruments is the development of 5D tracking systems, which provide charge, time, and three-dimensional coordinate measurements for each layer of the tracker. This approach integrates the 3D-spatial coordinate and charge |Z| measurements with layer-resolved timing information, to: i) enable improved track finding; ii) provide a redundant and independent time-of-flight system to standard scintillator based detectors; iii) remove spurious tracker hits; iv) contribute independent particle ID information to transition radiation detectors (TRDs) or calorimeters. A key benchmark for timing resolution in next-generation space detectors is a timing accuracy below 100 ps, while a finer resolution of less than 50 ps could allow to achieve additional break-through objectives such as precise isotope separation that could allow groundbreaking sensitivities in understanding cosmic-ray physics and searches for heavy nuclear antimatter in cosmic-rays.
Such performances are already well within the capabilities of pixel LGAD systems developed for accelerator physics application. However, this level of performance in space applications requires significant reduction in readout noise and further advances in front-end electronics and consumption to comply with the stringent requirements of space operations.
LGAD-based tracking systems are primarily being developed for high-energy and high-intensity collider detectors, where timing resolution below 30 ps and spatial resolution on the order of 10 micrometers are required. These developments position LGAD as an optimal candidate for 5D tracking devices in large-scale detectors. In space, radiation hardness requirements are largely less demanding than those for high-intensity collider experiments. However, the integration of LGAD microstrips devices, currently available in O(cm$^2$) area, to O(m$^2$) area detectors necessitates careful consideration on capacitance noise and power consumption.
To address these challenges, in the context of the Pentadimensional Tracking Space Detector project (PTSD) we are investigating and developing an innovative concept of LGAD Si-microstrip instrument based on a detector capacitance mitigation design. The integration of LGAD and standard Si-µstrip sensors in a serial readout architecture will allow for a combination of two-dimensional coordinates and timing measurements, while minimizing the detector capacitance. A breadboard laboratory model will validate the requirements and space qualification of LGAD Si-microstrips. In this contribution, the status of R&D activities which are currently progressing will be presented.
In addition, a conceptual flight-demonstrator is being designed to be housed in a 3U CubeSat platform. This demonstrator will serve as a proof-of-concept for 5D tracking in space and will open new diagnostic opportunities for cosmic-ray and gamma-ray detection. The successful development of LGAD Si-microstrip based 5D tracking will enable sensitivities to perform ambitious objectives otherwise hardly achievable in the next generation of space-borne cosmic-ray instruments, paving the way for future discoveries in particle astrophysics.
Resistive Silicon Detectors (AC-LGAD - RSD, DC-RSD) offer very good spatial (10-20 microns) and temporal resolution (30 - 40 ps) using large pixels (300 - 500 microns). RSDs are very thin, have 100% fill factor, and are radiation tolerant up to 1E15 n/cm2.
Given their low electrode density (for equal spatial resolution about a factor of 100 less than standard design), RSDs are ideal for low material budget/low power consumption applications.
RSDs have been proposed and developed by INFN at FBK, and now interesting developments are carried out in China (IME) and Japan (HKP, for EIC).
It is essential to maintain and foster the INFN's leading position in this technology and continue investing in experiments using it.
State-of-the-art silicon sensors are able to operate efficiently up to
fluences of 1E16/cm. Future frontier accelerators envisage the use of
tracking detectors in environments with fluences exceeding 1E17/cm.
The possible solution to overcome the present limit in radiation tolerance
is to exploit the recently observed saturation of radiation damage effects
on silicon, together with the usage of thin substrates, intrinsically less
affected by radiation. To cope with the small signal coming from thin
sensors, the Low-Gain Avalanche Diode (LGAD) design with internal
multiplication of the charge carriers represents the ideal framework.
An innovative design of the LGAD gain implant will be presented based on
an acceptor-donor compensation of the dopant atoms to preserve internal
gain above 1E16/cm and possibly up to 1E17/cm.
The presentation will introduce the basic concepts of the ERC
Consolidator Grant CompleX.
The goal is to pave the way for a new sensor design that can efficiently
perform precise tracking and timing measurements up to 1E17/cm and beyond.
As the ECFA detector research and development roadmap outlines, "revolutionary improvements in the performance of solid-state detectors are essential to meet the requirements of future experiments." In this context, Technology Computer-Aided Design (TCAD) is a highly valuable tool that can reduce costs and development time by providing a comprehensive understanding of the devices' physical behaviour before their manufacture. Ad-hoc developed numerical models for bulk and surface radiation damage effects can enhance TCAD tools, enabling the prediction of detector response evolution after irradiation and allowing designers to integrate this knowledge during the design phase.
This contribution will present the simulation outcomes that guided the design and predictive optimisation of the next-generation Low-Gain Avalanche Diodes (LGADs), such as Compensated LGADs and Resistive Silicon Detectors (RSDs).
Timepix4 is the latest application-specific integrated circuit (ASIC) developed by the Medipix4 international Collaboration at CERN. It features a 448x512 pixel matrix with a 55 μm pitch, designed for compatibility with a wide range of semiconductor sensors. This adaptability allows for optimization in various applications, including X-ray spectroscopy, high-energy particle detection, and medical imaging.
Timepix4 is fully prepared for Through-Silicon-Via (TSV) processing, enabling it to be tiled on four sides to cover large areas with negligible dead regions, while providing sub-200 ps time resolution. It supports two operation modes: frame-based and data-driven. In the frame-based mode, each event generating a signal above a programmable threshold increments a counter at the pixel level, and the counters of the entire matrix are read out synchronously with the core clock. In contrast, the data-driven mode operates such that a pixel transmits an output packet immediately after being hit. While the frame-based readout provides only photon-counting information, the data-driven readout also enables the measurement of Time-of-Arrival (ToA) and Time-over-Threshold (ToT), providing additional temporal and energy-related data. With a maximum hit rate of up to 5.0×10⁹ hits/mm²/s and the ability to handle data rates up to 160 Gbit/s, it offers high-performance capabilities for demanding applications.
INFN joined the Medipix4 collaboration in 2020. Two experiments have been funded by INFN-CSN5, MEDIPIX4 (2021-2024) and TIMEPIX4 (2025-2027) with the aim of studying and testing the possible applications of the read-out chips in a wide range of fields, from X-ray spectral imaging to nuclear medicine and dosimetry. The characterization of Timepix4 assemblies bump-bonded to various sensors, such as Si, CdTe, and GaAs, is currently ongoing at INFN. In this contribution, we will present an overview of this innovative technology and the results of the hands-on activities carried out.
This work presents a novel signal readout and data processing system based on a 32-bit ARM microcontroller for spectroscopic applications.
Previous attempts to develop microcontroller-based spectroscopy systems have often struggled with limitations such as low performance and high dead time, making them impractical for real-world use. This work introduces a highly customizable, full-stack solution that leverages modern microcontrollers to overcome these challenges while maintaining simplicity, flexibility, and low power consumption.
Although microcontroller-based solutions offer advantages such as reduced component count and ease of customization, they typically have lower performance compared to FPGA-based systems, which can limit certain capabilities. To address this, we present a readout system designed for a silicon drift detector (SDD) array, demonstrating key performance metrics achievable with a modern microcontroller.
In the presented implementation, a single microcontroller processes signals from two independent silicon sensors, requiring only four external components per channel. The system operates with a power consumption below 20 mA per channel and achieves zero dead time. It supports a throughput of up to 700k events/second per microcontroller, or 500k events/second per channel.
With its compact design and efficient performance, this microcontroller-based system is well-suited for portable detectors, embedded systems, and scalable front-end electronics in high-channel-count applications.
Integrating and packaging silicon detectors can be challenging due to constraints such as size, material compatibility, and system complexity. Choosing the right packaging solution is crucial for simplifying detector integration in custom applications.
This work presents an alternative approach developed and used in our laboratories for silicon detector packaging, where the detector is directly mounted on a commercial flexible printed circuit board (flex-PCB). Similar to conventional detector-on-PCB designs, the flex-PCB hosts essential passive components for power and signal filtering, a preamplification circuit, and a standard flat-flex cable (FFC) connector for back-end electronics. To ensure structural integrity and efficient thermal management, a metal frame is incorporated, serving as both a mechanical support and a thermal interface.
Compared to traditional detector-on-PCB systems, this approach offers several advantages, including an open backside for the detector, a reduced material budget in the active area, shorter input pad connections, improved thermal performance, better coefficient of thermal expansion (CTE) matching, and lower thermally induced stress. Additionally, its modular design makes it well-suited for scalable system integration and prototyping, allowing for easy adjustments in back-end systems without compromising the detector assembly.
As an example a monolithic 4 channel SDD detector has been integrated with the above described methodology and the resulting subsystem will be shown.
Transient High-Energy Sky and Early Universe Surveyor (THESEUS) is a
multi-instrument space mission concept candidate under European Space Agency (ESA) M7 Phase-Assessment study for medium size missions with an intended launch in 2037. The main goals of this mission include exploring the early universe by identifying and localising Gamma Ray Bursts (GRBs) at high redshifts (potentially up to z = 10 and beyond) and contributing to multimessenger time-domain astrophysics through extensive X/gamma-ray transient universe monitoring. Crucial to THESEUS success is its comprehensive transient detection and characterization capabilities, provided by wide and deep sky monitoring across a broad energy band (0.3 keV – 10 MeV) in which the X and Gamma-ray Imaging Spectrometer instrument (XGIS, 2 keV - 10 MeV) plays an essential role. Additionally, high positional accuracy (≤ 2 arcmin) and immediate transient identification with highly accurate redshift determination is achieved through the onboard Soft X-ray Imager (SXI, 0.3 - 5 keV) and the InfraRed Telescope (IRT), respectively. The XGIS is a set of two coded-mask monitor cameras capable of covering an unprecedented wide energy band (2 keV – 10 MeV), with imaging capabilities and location accuracy <15 arcmin up to 150 keV over a Field of View of 2 sr, a few hundreds eV energy resolution in the X-ray band (<30 keV) and timing resolution of around few μs based on a sandwich of monolithic SDDs (Silicon Drift Detectors) and scintillator crystals based X-ray and gamma-ray
detectors.
This presentation mainly focuses on the instrument design, detector working principle, and expected detector performances of the XGIS instrument, illustrating its evolution from the beginning of M5 Phase A to the current M7 Phase A with its unprecedented capabilities. Additionally, performance characterization of ORION, a very low noise multichip read out and processor electronics designed specifically for the XGIS instrument will be briefly presented.
The SiliciSpazio INFN project plans to evaluate LGAD and MAPS detectors for space applications. In parallel, the project aims to advance the packaging of such detectors, testing ultra-thin flexible solutions that could drastically improve payload miniaturisation and the design of the space electronics and harnesses. The packaging will involve the TAB bonding method, which provides higher reliability and improved high frequency performance compared to standard wire bonding. These methods are critical to the goal of the miniaturization of the packaging and to eliminate the need for encapsulation. The R&D will identify the main challenges to be overcome in order to transfer such state-of-the-art technologies from HEP to Space and focus on two main topics.
The first topic is to understand the extent to which detectors’ packaging can have a lightweight design and still provide robustness for space: flexible packaging will reduce over-engineering and an approach of stiffening only where needed will be applied. The second topic concerns the handling and bonding of miniaturized flexible cables, which will be extended to successive generations of MAPS detectors, which are larger than the ALTAI chips of 4.5 cm2, that were previously qualified for space by the Limadou collaboration in the HEPD-02 payload.
The ATLAS experiment at CERN is getting more and more ready to face the High-Luminosity era of the Large Hadron Collider, that will set harsher conditions in terms of radiation, luminosity and data stream for the ATLAS Detector. One of the key detector upgrade is the new all-silicion Inner Tracker, the ITk, that the ATLAS Collaboration is building to replace the ATLAS Inner Detector for the High-Luminosity phase. The ITk is made by a pixel detector at smaller radius and a strip detector surrounding it. The ITk Pixel detector innermost layer will be expose at unprecedented radiation levels: highly radiation hard 3D hybrid pixel sensors has been selected to instrument the it, while all the other layer will use planar sensors.
Hybridization of 3D sensors plays a key role in the project and presents several challenges, given the natural mechanical fragility of 3D sensors. The Institutes involved in the assembly of the module for the innermost layer together with two hybridization company (Leonardo SPA and The Fraunhofer Institute for Reliability and Microintegration IZM) have undergone a long process of qualification to study and improve the quality of the process.
In this talk, we will focus and the qualification procedure that has been adopter to test the quality of the bump bonding connection of both vendors. We will present several ways for investigating the bump connectivity based on cross-talk, x-ray scan or electrical noise. Finally we will present the effects on bumps due to thermal cycles, where we investigating any possibility of delamination between the 3D sensors and the electronics.
Highlights from the sessions, feedback by Early career scientists, by senior colleagues, CSN5 and INFN management