arXiv subjects

M. T. Lucchini

Publications and source records attributed to M. T. Lucchini.

7 recordsLinked to original sources

arXiv2026

Cherenkov and scintillation light separation in BGO and BSO crystals coupled to SiPMs for dual-readout electromagnetic calorimetry at future colliders

We report on the separation of Cherenkov and scintillation light in BGO and BSO crystals read out with silicon photomultipliers (SiPMs). The two light components are disentangled on an event-by-event basis by combining optical filtering with waveform template fitting, exploiting their distinct spectral and temporal characteristics. Measurements were carried out using high-energy muon and positron beams at the CERN SPS North Area, demonstrating Cherenkov yields of up to $\sim$150 ph.e./GeV in electromagnetic showers. This work provides the first demonstration of Cherenkov-scintillation separation in BGO and BSO crystals with SiPM readout, supporting the use of this technology as a building block for a dual-readout electromagnetic calorimeter, as foreseen in the IDEA detector concept for a future $e^+e^-$ Higgs factory.

physics.ins-det↗

arXiv2025

The CMS Barrel Timing Layer: test beam confirmation of module timing performance

First of its kind, the barrel section of the MIP Timing Detector is a large area timing detector based on LYSO:Ce crystals and SiPMs which are required to operate in an unprecedentedly harsh radiation environment (up to an integrated fluence of $2\times10^{14}$ 1 MeV $n_{eq}/cm^2$). It is designed as a key element of the upgrade of the existing CMS detector to provide a time resolution for minimum ionizing particles in the range between 30-60 ps throughout the entire operation at the High Luminosity LHC. A thorough optimization of its components has led to the final detector module layout which exploits 25 $\rm μm$ cell size SiPMs and 3.75 mm thick crystals. This design achieved the target performance in a series of test beam campaigns. In this paper we present test beam results which demonstrate the desired performance of detector modules in terms of radiation tolerance, time resolution and response uniformity.

physics.ins-det↗

arXiv2024

Optimization of LYSO crystals and SiPM parameters for the CMS MIP timing detector

For the High-Luminosity (HL-LHC) phase, the upgrade of the Compact Muon Solenoid (CMS) experiment at CERN will include a novel MIP Timing Detector (MTD). The central part of MTD, the barrel timing layer (BTL), is designed to provide a measurement of the time of arrival of charged particles with a precision of 30 ps at the beginning of HL-LHC, progressively degrading to 60 ps while operating in an extremely harsh radiation environment for over a decade. In this paper we present a comparative analysis of the time resolution of BTL module prototypes made of LYSO:Ce crystal bars read out by silicon photo-multipliers (SiPMs). The timing performance measured in beam test campaigns is presented for prototypes with different construction and operation parameters, such as different SiPM cell sizes (15, 20, 25 and 30 $\rm μm$), SiPM manufacturers and crystal bar thicknesses. The evolution of time resolution as a function of the irradiation level has been studied using non-irradiated SiPMs as well as SiPMs exposed up to $2\times 10^{14}~n_{eq}/cm^2$ fluence. The key parameters defining the module time resolution such as SiPM characteristics (gain, photon detection efficiency, radiation induced dark count rate) and crystal properties (light output and dimensions) are discussed. These results have informed the final choice of the MTD barrel sensor configuration and offer a unique starting point for the design of future large-area scintillator-based timing detectors in either low or high radiation environments.

physics.ins-det↗

arXiv2024

TOFHIR2: The readout ASIC of the CMS Barrel MIP Timing Detector

The CMS detector will be upgraded for the HL-LHC to include a MIP Timing Detector (MTD). The MTD will consist of barrel and endcap timing layers, BTL and ETL respectively, providing precision timing of charged particles. The BTL sensors are based on LYSO:Ce scintillation crystals coupled to SiPMs with TOFHIR2 ASICs for the front-end readout. A resolution of 30-60 ps for MIP signals at a rate of 2.5 Mhit/s per channel is expected along the HL-LHC lifetime. We present an overview of the TOFHIR2 requirements and design, simulation results and measurements with TOFHIR2 ASICs. The measurements of TOFHIR2 associated to sensor modules were performed in different test setups using internal test pulses or blue and UV laser pulses emulating the signals expected in the experiment. The measurements show a time resolution of 24 ps initially during Beginning of Operation (BoO) and 58 ps at End of Operation (EoO) conditions, matching well the BTL requirements. We also showed that the time resolution is stable up to the highest expected MIP rate. Extensive radiation tests were performed, both with x-rays and heavy ions, showing that TOFHIR2 is not affected by the radiation environment during the experiment lifetime.

physics.ins-det↗

arXiv2023

Integration of thermo-electric coolers into the CMS MTD SiPM arrays for operation under high neutron fluence

The barrel section of the novel MIP Timing Detector (MTD) will be constructed as part of the upgrade of the CMS experiment to provide a time resolution for single charged tracks in the range of $30-60$ ps using LYSO:Ce crystal arrays read out with Silicon Photomultipliers (SiPMs). A major challenge for the operation of such a detector is the extremely high radiation level, of about $2\times10^{14}$ 1 MeV(Si) Eqv. n/cm$^2$, that will be integrated over a decade of operation of the High Luminosity Large Hadron Collider (HL-LHC). Silicon Photomultipliers exposed to this level of radiation have shown a strong increase in dark count rate and radiation damage effects that also impact their gain and photon detection efficiency. For this reason during operations the whole detector is cooled down to about $-35^{\circ}$C. In this paper we illustrate an innovative and cost-effective solution to mitigate the impact of radiation damage on the timing performance of the detector, by integrating small thermo-electric coolers (TECs) on the back of the SiPM package. This additional feature, fully integrated as part of the SiPM array, enables a further decrease in operating temperature down to about $-45^{\circ}$C. This leads to a reduction by a factor of about two in the dark count rate without requiring additional power budget, since the power required by the TEC is almost entirely offset by a decrease in the power required for the SiPM operation due to leakage current. In addition, the operation of the TECs with reversed polarity during technical stops of the accelerator can raise the temperature of the SiPMs up to $60^{\circ}$C (about $50^{\circ}$C higher than the rest of the detector), thus accelerating the annealing of radiation damage effects and partly recovering the SiPM performance.

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arXiv2022

Comparative characterization study of LYSO:Ce crystals for timing applications

Cerium-doped Lutetium-Yttrium Oxyorthosilicate (LYSO:Ce)is one of the most widely used Cerium-doped Lutetium based scintillation crystals. Initially developed for medical detectors it rapidly became attractive for High Energy Particle Physics (HEP) applications, especially in the frame of high luminosity particle colliders. In this paper, a comprehensive and systematic study of LYSO:Ce ($[Lu_{(1-x)}Y_x]_2SiO_5$:$Ce$) crystals is presented. It involves for the first time a large number of crystal samples (180) of the same size from a dozen of producers.The study consists of a comparative characterization of LYSO:Ce crystal products available on the market by mechanical, optical and scintillation measurements and aims specifically, to investigate key parameters of timing applications for HEP.

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arXiv2022

Precision timing for collider-experiment-based calorimetry

In this White Paper for the 2021 Snowmass process, we discuss aspects of precision timing within electromagnetic and hadronic calorimeter systems for high-energy physics collider experiments. Areas of applications include particle identification, event and object reconstruction, and pileup mitigation. Two different system options are considered, namely cell-level timing capabilities covering the full detector volume, and dedicated timing layers integrated in calorimeter systems. A selection of technologies for the different approaches is also discussed.

physics.ins-det↗