Future High Energy Physics Experiments Research Articles

QCLUE: a quantum clustering algorithm for multi-dimensional datasets

Clustering algorithms are at the basis of several technological applications, and are fueling the development of rapidly evolving fields such as machine learning. In the recent past, however, it has become apparent that they face challenges stemming from datasets that span more spatial dimensions. In fact, the best-performing clustering algorithms scale linearly in the number of points, but quadratically with respect to the local density of points. In this work, we introduce qCLUE, a quantum clustering algorithm that scales linearly in both the number of points and their density. qCLUE is inspired by CLUE, an algorithm developed to address the challenging time and memory budgets of Event Reconstruction (ER) in future High-Energy Physics experiments. As such, qCLUE marries decades of development with the quadratic speedup provided by quantum computers. We numerically test qCLUE in several scenarios, demonstrating its effectiveness and proving it to be a promising route to handle complex data analysis tasks – especially in high-dimensional datasets with high densities of points.

A Time-over-Threshold based analog front-end in 28 nm CMOS for pixel detectors in future colliders

This work is concerned with the design, in a 28 nm CMOS technology, of an analog front-end processor for the readout of pixel detectors in future high energy physics experiments. The front-end circuit being developed consists of a shaper-less architecture which leverages the Time-Over-Threshold (ToT) technique for the analog-to-digital conversion of the signal from the detector. Post-layout simulation results show that the circuit, operated with a nominal current close to 4 uA and a supply voltage of 0.9 V, is able to operate at a threshold below 1000 electrons.

ALLEGRO FCC-ee detector concept & Noble liquid calorimetry

ALLEGRO is a proposed FCC-ee general-purpose detector concept with a noble liquid (NL) electromagnetic calorimeter (ECAL) as a central feature. Calorimetry based on liquified noble gases is a well-proven technology that has been successfully applied in numerous high-energy physics (HEP) experiments. This technology provides excellent energy resolution, linearity, stability, uniformity and timing properties at a reasonable cost, making it a strong candidate for future HEP experiments. By using multi-layer printed circuit boards as readout electrodes, we can build a calorimeter with almost arbitrarily high granularity. This in turn allows for four-dimensional imaging, machine learning algorithms and particle-flow reconstruction to be fully exploited. In this proceedings contribution we give an overview to the ALLEGRO concept and present the ongoing R&D work for adapting NL calorimetry to an ECAL of a lepton collider experiment. In addition to simulation studies and expected performance, we show results on signal extraction and noise mitigation studies made with readout electrode prototypes and compare the measurements to simulations, as well as discuss test results of absorber prototypes. In addition we present progress of the mechanical design project and status of the barrel ECAL test-beam prototype module development.

TCAD approach for negative capacitance ferroelectric devices for radiation detection applications

Negative capacitance (NC) emerges as a promising technology for low-power, high-performance transistors. The HiEnD project intends to analyze and design high-energy efficient electronic devices based on innovative ferroelectric materials. It explores NC technology for high-resolution tracking detectors in future high-energy physics experiments. It aims to create ultra-thin, radiation-resistant devices for superior signal detection in harsh environments. This paper presents detailed modeling, simulation results, and a comparison with experimental data, highlighting the potential of the developed methodology but also of the technology for the realization of compact, high-performance detectors. Advanced Technology CAD modeling has been employed to investigate the potentiality of NC devices in unconventional application domains, such as high-energy physics experiments. Numerical simulations, capable of verifying experimental results, enhance predictive power, reducing time and cost in detector design and testing.

First results on monolithic CMOS detector with internal gain

In this paper we report on a set of characterisations carried out on the first monolithic LGAD prototype integrated in a customised 110 nm CMOS process having a depleted active volume thickness of 48 μm. This prototype is formed by a pixel array where each pixel has a total size of 100 μm× 250 μm and includes a high-speed front-end amplifier. After describing the sensor and the electronics architecture, both laboratory and in-beam measurements are reported and described. Optical characterisations performed with an IR pulsed laser setup have shown a sensor internal gain of about 2.5. With the same experimental setup, the electronic jitter was found to be between 50 ps and 150 ps, depending on the signal amplitude. Moreover, the analysis of a test beam performed at the Proton Synchrotron (PS) T10 facility of CERN with 10 GeV/c protons and pions indicated that the overall detector time resolution is in the range of 234 ps to 244 ps. Further TCAD investigations, based on the doping profile extracted from C(V) measurements, confirmed the multiplication gain measured on the test devices. Finally, TCAD simulations were used to tune the future doping concentration of the gain layer implant, targeting sensors with a higher avalanche gain. This adjustment is expected to enhance the timing performance of the sensors of the future productions, in order to cope with the high event rate expected in most of the near future high-energy and high-luminosity physics experiments, where the time resolution will be essential to disentangle overlapping events and it will also be crucial for Particle IDentification (PID).

Pressure resistance characterisation of vascular networks embedded in carbon composites for high energy physics applications

In state-of-the-art tracking detectors, lightweight carbon composite structures support the pixel or micro-strip sensors and provide the main thermal path between the silicon and a network of metallic or plastic pipes containing a cooling fluid. Despite the good results obtained with this design approach, the challenges associated with future high energy physics (HEP) experiments demand even lighter and more efficient technologies. In this regard, replacing the existing piping with a network of channels directly embedded in the composite laminates represents a promising solution to improve the thermal coupling, which also offers additional gains in terms of mass and thermo-elastic stability.While some research has been devoted to assessing the mechanical and thermal performance of such laminates, limited information about their resistance to internal pressure is currently available in the literature. This lack of data constitutes an important obstacle for the use of vascular networks in future HEP applications, which the present paper aims to address.Experimental methods were used to investigate the pressure resistance of channels embedded in carbon composite laminates. Modified poly (lactic) acid (PLA) preforms were embedded in carbon-fibre epoxy laminates. A post-cure vaporization technique removed the PLA, thus producing plates with longitudinal channels. Destructive tests were conducted to determine the burst pressure of the plates depending on the lay-up and the cross-section geometry of the channels. Both circular and oblong channels were evaluated, and various reinforcement techniques were explored to enhance the pressure resistance of the laminates. Micro-graphic examinations and X-ray micro-computed tomography were employed to gain a better understanding of the microstructure and the failure mechanisms of the plates.Plates with circular channels measuring 1.75 mm in diameter, embedded in [0/90/0]S laminates and reinforced with 2 mm lay length fuzzy carbon fibre over-braids, achieved burst pressures exceeding 45 MPa. This result, which is approximately an order of magnitude greater than that obtained for the equivalent non-reinforced laminates, demonstrates the enormous potential of this technology for future particle detectors.

All-optical source size and emittance measurements of laser-accelerated electron beams

Novel schemes for generating ultralow emittance electron beams have been developed in past years and promise compact particle sources with excellent beam quality suitable for future high-energy physics experiments and free-electron lasers. Recent theoretical work has proposed a laser-based method capable of resolving emittances in the sub 0.1 mm mrad regime by modulating the electron phase space ponderomotively. Here we present the first experimental demonstration of this scheme using a laser wakefield accelerator. The observed emittance and source size are consistent with published values. We also show calculations demonstrating that tight bounds on the upper limit for emittance and source size can be derived from the “laser-grating” method even in the presence of low signal to noise and uncertainty in laser-grating parameters. Published by the American Physical Society 2024

Dual use driver for high speed links transmitters in the future high energy physics experiments

The paper presents the Dual Use Driver (DUDE) for high speed links, a circuit designed for the Demonstrator ASIC for Radiation-Tolerant Transmitter in 28 nm CMOS (DART28) developed under the EP-R&D programme on technologies for future high energy physics experiments. The driver operates at 25.6 Gbps and it allows driving both 100 Ω transmission lines and optical Ring Modulators (RMs) integrated in a photonics integrated circuit (PIC). The driver includes configurable pre-emphasis. The device will allow to demonstrate the feasibility of wavelength division multiplexing (WDM) optical links operating with bandwidths in excess of 100 Gbps per fiber that are capable of sustaining total ionizing radiation doses up to 10 MGy.

The k4Clue package: Empowering future collider experiments with the CLUE algorithm

High granularity calorimeters have become increasingly crucial in modern particle physics experiments, and their importance is set to grow even further in the future. The CLUstering of Energy (CLUE) algorithm has shown excellent performance in clustering calorimeter hits in the High Granularity Calorimeter (HGCAL) developed for the Phase-2 upgrade of the CMS experiment. In this paper, the suitability of the CLUE algorithm for future collider experiments has been investigated and its capabilities tested outside the HGCAL reconstruction software. To this end, a new package, k4Clue, was developed which is now fully integrated into the Gaudi software framework and supports the EDM4hep data format for inputs and outputs. The performance of CLUE was demonstrated in three detectors for future colliders: CLICdet for the CLIC accelerator, CLD for the FCC-ee collider and a second calorimeter based on Noble Liquid technology also proposed for FCC-ee. Excellent reconstruction performance was observed for single photon events, even in the presence of noise, and the results are compatible with the performance of the algorithms used currently as the baseline for shower reconstruction in future e+e−-colliders. Moreover, CLUE demonstrates impressive timing capabilities, outperforming the current baseline algorithms and this advantage remains consistent regardless of the number of input hits. This work highlights the adaptability and versatility of the CLUE algorithm for a wide range of experiments and detectors and the algorithm’s potential for future high-energy physics experiments beyond CMS.

Radiation resistant optical components for high energy physics detectors

New detectors for future high-energy physics experiments will operate under unprecedented radiation dose rates. This condition requires improved radiation resistance on detector equipment. The consequent development of new materials, particularly optical materials, becomes crucial. In this work, optical components mean reflectors, light absorbers, or light transmitters. These materials, reflectors or light transmitters, are needed in detectors primarily to collect and transmit light from the scintillator to the PMT. When it comes to light absorbers, they are required to protect the detector from light from the environment. This work aims at studying selected optical materials with improved properties (functional and optical) and radiation resistance that can be used in new detectors at the Large Hadron Collider (LHC) experiments. Light transmittance, optical reflection, thermal characteristics, and radiation resistance were investigated to evaluate the proposed materials.We have developed optical systems based on siloxanes to continue our previous developments of radiation-resistant materials for radiation detectors. We also report a study of several reflective materials and light absorber introduced into the siloxane. Investigations have shown that these systems are radiation resistant to doses of at least 1 MGy.Tested samples were irradiated at linear electron accelerator LUE-40 in the National Science Center Kharkiv Institute of Physics and Technology (KIPT). The accelerated electrons were sent to the heavy complex targets to deliver the irradiation with gamma or neutron fluxes. The consequent gamma and neutron fluxes and doses were estimated with the GEANT4 simulation.

Система оцінки якості монолітних активних мікропіксельних детекторів

A system for quality assessment of micropixel detectors is presented. The system includes a laser scanning microprobe and a setup for studying the response of micro detectors to minimum ionizing particles. The results of the validation of the developed system indicate its suitability for assessing the quality of the latest monolithic active pixel sensors (MAPS), promising elements of large-area tracking systems for future high-energy physics experiments. Comparison of MAPS with the double-sided microstrip detectors of the CBM experiment (FAIR, Darmstadt) indicates the feasibility of the upgrade of its Silicon Tracking System using MAPS.

Optimizing Time Resolution Electronics for DMAPs

Depleted Monolithic Active Pixel Sensors (DMAPSs) are foreseen as an interesting choice for future high-energy physics experiments, mainly because of the reduced fabrication costs. However, they generally offer limited time resolution due to the stringent requirements of area and power consumption imposed by the targeted spatial resolution. This work describes a methodology to optimize the design of time-to-digital converter (TDC)-based timing electronics that takes advantage of the asymmetrical shape of the pulse at the output of the analog front-end (AFE). Following that methodology, a power and area efficient implementation fully compatible with the RD50-MPW3 solution is proposed. Simulation results show that the proposed solution offers a time resolution of 2.08 ns for a range of energies from 1000 e− to 20,000 e−, with minimum area and zero quiescent in-pixel power consumption.

Integration of CVD graphene in gaseous electron multipliers for high energy physics experiments

To enhance the performance of micro-patterned gaseous detectors (MPGDs) to meet the challenging requirements of future high energy physics (HEP) experiments, two-dimensional (2D) materials are attractive candidates to address the back flow of positive ions, which affects detector performance by distorting electric field lines. In this context, graphene is promising to work as selective filter for ion back flow suppression, being transparent to electrons while at the same time blocking ions. Also, graphene membranes can physically separate drift and amplification regions of the detectors, offering additional flexibility in the choice of gas mixtures and allowing independent optimizations of detector sensitivity and electron multiplication processes. Here we present an approach to integrate graphene grown via chemical vapor deposition (CVD) on gaseous electron multiplier (GEM) prototypes via a wet transfer procedure in order to suspend graphene over thousands of holes with 60 μm diameter and overcome the challenges encountered due to process steps involving liquids, mostly related with the capillary effects during drying and evaporation of them. In order to overcome the risk of damaging the membrane and decreasing the yield of suspended 2D material membranes, critical point dryer (CPD) and inverted floating method (IFM) procedures are investigated. In addition to the necessity to cover the full holes in the active area, polymeric residuals have to be minimized in order to evaluate the graphene transparency at the electron energies (i.e., < 15 eV) typically obtained in the operating conditions, measurements in these energy ranges are still not deeply investigated.

One-Dimensional Position-Sensitive LGAD With a DC Coupled and Resistive Charge Division Mechanism

Low-gain avalanche detectors (LGADs) are promising candidates for four-dimensional (4D) tracking detectors in future high-energy physics (HEP) experiments, offering high position and time resolution. However, conventional pixel array LGADs suffer from large dead areas between pixels and require a large number of readout channels, resulting in a poor spatial resolution and high cost. In this paper, we present a one-dimensional position-sensitive LGAD (1D PS-LGAD) based on DC coupling and a resistive charge division mechanism. The 1D PS-LGAD features two cathodes and one anode, with two-dimensional position coordinates obtained by cross-placing two 1D PS-LGADs. With an active thickness of 50 μm and an active area of 2.7 mm × 2.7 mm, a 1D PS-LGAD demonstrated an average position measurement error (PME) of 32.2 ±35.4 μm, accounting for 1.2% of the side length of the active area with a 100% fill factor. The coincidence time resolution and position resolution were 8.8 ps and 22.5 μm, respectively, at the center of the device for incident 532 nm light with a spot diameter of approximately 25 μm and a mean photoelectron number (MPEN) of 6000 when the reverse voltage was 620 V.

Development and test of innovative Low-Gain Avalanche Diodes for particle tracking in 4 dimensions

The MIUR PRIN 4DInSiDe collaboration aims at developing the next generation of 4D (i.e., position and time) silicon detectors based on Low-Gain Avalanche Diodes (LGAD) that guarantee to operate efficiently in the future high-energy physics experiments. To this purpose, different areas of research have been identified, involving the development, design, fabrication and test of radiation-hard devices. This research has been enabled thanks to ad-hoc advanced TCAD modelling of LGAD devices, accounting for both technological issues as well as physical aspects, e.g. different avalanche generation models and combined surface and bulk radiation damage effects modelling. In this contribution, it is reviewed the progress and the relevant detector developments obtained during the research activities in the framework of the 4DInSiDe project. • TCAD modelling for the design of radiation-hard LGAD sensors for 4D tracking. • Gain layer compensation, (p ＋ - and n ＋ -doping) to preserve the gain at high fluences. • New design approach to resistive read-out sensors: DC-coupled RSD. • DC-RSD employs a direct coupling of the resistive layer to the read-out pads. • DC-coupled low resistivity strips between read-out pads to improve the resolution.

Characterization of Lab-on-Fiber-based dosimeters in ultra-high dose radiation fields

Next generation High Energy Physics (HEP) accelerators will require new devices and technologies capable of operating in extreme environments characterized by ultra-high radiation doses up to the MGy levels. To this aim, we report on an innovative Lab-On-Fiber (LOF) probe for the real-time dose monitoring. The proposed platform is based on a metallo-dielectric nanostructured grating made of gold and poly(methyl methacrylate) (PMMA) patterned on the termination of single mode fibers. The nanostructure has been judiciously designed to support a plasmonic resonance in the reflection spectrum occurring at near infrared wavelengths. Electron beam lithography was used for the fabrication of two LOF prototypes, which in turn, were exposed to X-rays with a total dose of 2.02 MGy and a dose rate of 88 kGy/h. Reflection spectra acquired during the irradiation revealed a clear dependence of the LOF resonance wavelength and depth on the absorbed dose, confirming the outcomes of our previous proton campaign. Morphological characterization of the irradiated samples showed that the main radiation induced effect is the reduction of the PMMA thickness (ranging between 26 % and 40 %), which in turn strongly affects the resonance behavior. Quantitative morphological measurements have been used to achieve a fair and objective correlation with our numerical modelling. Moreover, we investigated the effect of ultra-high doses of several radiation types, including X-rays, electrons and protons, on the thickness of PMMA nanolayers deposited on planar substrates. Experimental results revealed that the amount of absorbed dose (1.9–16.06 MGy) is the main parameter affecting the PMMA relative compaction (9.5–59.1 %), while the influence of the radiation type, dose rate and initial PMMA thickness can be considered negligible. Overall, these results pave the way to the development of radiation type independent PMMA assisted LOF dosimeters operating at MGy doses for the radiation monitoring in future HEP experiments.

Performance of neutron-irradiated 4H-silicon carbide diodes subjected to alpha radiation

The unique electrical and material properties of 4H-silicon-carbide (4H-SiC) make it a promising candidate material for high rate particle detectors. In contrast to the ubiquitously used silicon (Si), 4H-SiC offers a higher carrier saturation velocity and larger breakdown voltage, enabling a high intrinsic time resolution and mitigating pile-up effects. Additionally, as radiation hardness requirements grow more demanding in the context of future high luminosity high energy physics experiments, wide-bandgap materials such as 4H-SiC could offer better performance due to low dark currents and higher atomic displacement thresholds. In this work, the detector performance of 50 µm thick 4H-SiC p-in-n planar pad sensors was investigated at room temperature, using an 241Am alpha source at reverse biases of up to 1100 V. Samples subjected to neutron irradiation with fluences of up to 1 × 1016 neq/cm2 were included in the study in order to quantify the radiation hardness properties of 4H-SiC. A calibration of the absolute number of collected charges was performed using a GATE simulation. The obtained results are compared to previously performed UV transient current technique (TCT) studies. Samples exhibit a drop in charge collection efficiency (CCE) with increasing irradiation fluence, partially compensated at high reverse bias voltages far above full depletion voltage. At fluences of 5 × 1014 neq/cm2 and 1 × 1015 neq/cm2, CCEs of 64 % and 51 % are obtained, decreasing to 15 % at 5 × 1015 neq/cm2. A plateau of the collected charges is observed in accordance with the depletion of the volume the alpha particles penetrate for an unirradiated reference detector. For the neutron-irradiated samples, such a plateau only becomes apparent at higher reverse bias, roughly 600 V and 900 V for neutron fluences of 5 × 1014 neq/cm2 and 1 × 1015 neq/cm2. For the highest investigated fluence, CCE behaves almost linearly with increasing reverse bias. Compared to UV-TCT measurements, the reverse bias required to deplete a sensitive volume covering full energy deposition is lower, due to the small penetration depth of the alpha particles. At the highest reverse bias, the measured CCE values agree well with earlier UV-TCT studies, with discrepancies between 1% and 5%.

First characterization results of ARCADIA FD-MAPS after X-ray irradiation

The ARCADIA collaboration is developing fully-depleted (FD) Monolithic Active Pixel Sensors (MAPS) in a 110 nm CMOS process in collaboration with LFoundry. The sensor design incorporates an n+ collection node within a n-type epi-layer on top of a high-resistivity n-type substrate and p+ backside. Thus, the pn-junction sits on the backside and through an applied backside bias, the full substrate gets depleted. The targeted applications of this technology range from future high energy physics experiments to space applications, and medical and industrial scanners. Together, these applications set the minimum requirements on the detector: data collection at hit rates of (10–100) MHz/cm2, full signal processing within (1–10) μs, maximum power consumption (5–20) mW/cm2 and radiation tolerances of up to 3.4 Mrad or 6.2 × 1012 1 MeV neutron equivalent fluence. In order to proof the performance of the technology, a demonstrator chip of 512 × 512 pixels with 25 μm pitch was designed and fabricated in a first engineering run in 2021, together with additional test structures of pixel and strip arrays with different pitches and sensor geometries. The production run has produced functional passive and active pixel matrices. Earlier studies have shown that positive oxide charges and traps at the Si-SiO2 interface, introduced by ionising radiation, affect the depletion region around the collection electrode, increasing the pixel capacitance. By varying the gap size between collection node and pwells, the geometry can be optimised to keep the capacitance low also after irradiation. To study the performance after irradiation, of the optimised diode designs, the passive pixel matrices were irradiated with doses up to 10 Mrad (SiO2) using a X-ray tube with a Tungsten anode. The measurements are complemented by TCAD simulations. The maximum capacitance increase after irradiation was found to reach 6 and 12 fF/pixel for pixel pitches of 25 and 50 μm, respectively. The relative capacitance increase after irradiation has hereby been found to reach up to 250% after a dose of 10 Mrad.

Radiation-tolerant all-digital clock generators for HEP applications

The emergence of high-precision timing systems in High Energy Physics motivates new developments in the domain of clock generation and distribution. Particularly, when considering the challenges arising from adopting advanced deep-submicron CMOS technology nodes, all-digital PLL and clock and data recovery (CDR) architectures constitute a promising option for future high energy physics (HEP) experiments. Both LC oscillator and ring oscillator-based all-digital PLL/CDR blocks for front-end ASICs were studied, designed, manufactured and characterized. Their design, the hardening considerations, as well as the performance obtained with these circuits are presented in this article.

Analysis of activation energy and conductivity in 1 MeV neutron irradiated silicon diodes

In a highly 1 MeV neutron-irradiated silicon (Si) diode, an ohmic current-voltage (I-V) behaviour is observed, with the ohmic region increasing with radiation fluence. Reverse current (minority carrier density) increasing more drastically than forward current (majority carrier density) explains the conductivity-type inversion of material-based devices from n-to p-type after irradiation. The reverse current activation energy decreases from 0.86 eV for unirradiated Si diodes to 0.54 eV for the highest irradiated diodes, confirming the material conductivity-type inversion. The activation energy is independent of the radiation fluence just below the Si intrinsic Fermi energy, showing that when the defects near the centre of the Si band gap dominate the conduction mechanism, diode properties are independent of incident radiation. Despite its detrimental effects, radiation can improve the stability of diode properties. The stability of the properties is important for the fabrication of sensors for current and future high-energy physics experiments. The improved stability is because of radiation-induced defect levels close to the centre of the band gap that behave as generation-recombination (g-r) centres in Si.