arXiv subjects

Adriano Lai

Publications and source records attributed to Adriano Lai.

11 recordsLinked to original sources

arXiv2025

New developments in 3D-trench electrode sensors

Future high-luminosity hadron collider experiments feature unprecedented levels of event pile-up and extreme radiation environments, calling for sensors capable of 4D tracking, even after significant radiation damage. To this purpose, 3D sensors represent a viable solution, since they provide excellent radiation tolerance and very good temporal resolution. In particular, owing to the uniform electric field and weighting field distributions, 3D-trench electrode sensors from the INFN TIMESPOT project have shown a temporal resolution of $\sim$10 ps after irradiation fluences up to 1$\times$10$^{17}$ 1-Mev n$_{eq}$/cm$^2$. In spite of the excellent performance of these sensors, 3D-trench pixel technology is not yet fully established and the fabrication yield is not yet adequate for the production of large size pixel sensors. To improve the potential of the 3D-trench concept for large-area sensors, a new batch of sensors was designed at the University of Trento and fabricated at FBK, as part of the AIDA Innova project. Besides introducing some process improvements, this batch includes two different sensor variants: the standard one with continuous ohmic trenches, and a modified one with dashed ohmic trenches. On-wafer electrical test results show that most of the sensors have low leakage current and high breakdown voltage. Moreover, the fabrication yield for the new design variant is higher than that of the standard design.

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arXiv2023

Timing performances of front-end electronics with 3D-trench silicon sensors

Detectors based on pixels with timing capabilities are gaining increasing importance in the last years. Next-to-come high-energy physics experiments at colliders require the use of time information in tracking, due to the expected levels of track densities in the foreseen experimental conditions. A promising solution to gain high-resolution performance at the sensor level is given by so-called 3D silicon sensors. The excellent intrinsic time resolution of a special case of 3D sensors, the trench type, is limited by residual non-uniformities in the duration of the induced currents. The intrinsic contribution of the sensor to the total time resolution of the system, when the detector is coupled to a front-end electronics, depends on the characteristics of the electronics itself and can be minimized with a proper design. This paper aims to analyze the possible performance in the timing of a typically-used front-end circuit, the Trans-Impedance Amplifier, considering different possible configurations. Evidence of the preferred modes of operation in sensor read-out for timing measurement will be given.

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arXiv2023

Intrinsic timing properties of ideal 3D-trench silicon sensor with fast front-end electronics

This paper describes the fundamental timing properties of a single-pixel sensor for charged particle detection based on the 3D-trench silicon structure. We derive the results both analytically and numerically by considering a simple ideal sensor and the corresponding fast front-end electronics in two different case scenarios: ideal integrator and real fast electronics (trans-impedance amplifier). The particular shape of the Time of Arrival (TOA) distribution is examined and the relation between the time resolution and the spread of intrinsic charge collection time is discussed, by varying electronics parameters and discrimination thresholds. The results are obtained with and without simulated electronics noise. We show that the 3D-trench sensors are characterized by a $synchronous~region$, i.e. a portion of the active volume which leads to the same TOA values when charged particles cross it. The synchronous region size is dependent on the front-end electronics and discrimination threshold, and the phenomenon represents an intrinsic physical effect that leads to the excellent time resolution of these sensors. Moreover, we show that the TOA distribution is characterized by an intrinsic asymmetry, due to the 3D geometry only, that becomes negligible in case of significant electronics jitter.

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arXiv2023

Front-end Electronics for Timing with pico-seconds precision using 3D Trench Silicon Sensors

The next generation of collider experiments require tracking detectors with extreme performance capabilities in terms of spatial resolution (tens of $μ\text{m}$), radiation hardness ($10^{17}~1~$MeV n$_{eq}/$cm$^2$) and timing resolution (tens of ps). 3D silicon sensors, recently developed within the TimeSPOT initiative, offer a viable solution to cope with such demanding requirements. In order to accurately characterize the timing performance of these new sensors, several read-out boards, based on discrete active components, have been designed, assembled, and tested. The same electronics is also suitable for characterization of similar pixel sensors whenever timing performance in the order and below 10 ps is a requirement. This paper describes the general characteristics needed by front-end electronics to exploit solid-state sensors with fast timing capabilities and in particular, showcases the performance of the developed electronics in the testing and characterization of fast 3D silicon sensors.

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arXiv2022

Timespot1: A 28nm CMOS Pixel Read-Out ASIC for 4D Tracking at High Rates

We present the first characterization results of Timespot1, an ASIC designed in CMOS 28 nm technology, featuring a $32 \times 32$ pixel matrix with a pitch of $55 ~ \mu m$. Timespot1 is the first small-size prototype, conceived to readout fine-pitch pixels with single-hit time resolution below $50 ~ ps_\text{rms}$ and input rates of several hundreds of kilohertz per pixel. Such experimental conditions will be typical of the next generation of high-luminosity collider experiments, from the LHC run5 and beyond. Each pixel of the ASIC includes a charge amplifier, a discriminator, and a Time-to-Digital Converter with time resolution indicatively of $22.6 ~ ps_\text{rms}$ and maximum readout rates (per pixel) of $3 ~ MHz$. To respect system-level constraints, the timing performance has been obtained keeping the power budget per pixel below $40 ~ \mu W$. The ASIC has been tested and characterised in the laboratory concerning its performance in terms of time resolution, power budget and sustainable rates. The ASIC will be hybridized on a matched $32 \times 32$ pixel sensor matrix and will be tested under laser beam and Minimum Ionizing Particles in the laboratory and at test beams. In this paper we present a description of the ASIC operation and the first results obtained from characterization tests concerning its performance.

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arXiv2022

4-Dimensional Trackers

4-dimensional (4D) trackers with ultra fast timing (10-30 ps) and very fine spatial resolution (O(few $μ$m)) represent a new avenue in the development of silicon trackers, enabling new physics capabilities beyond the reach of the existing tracking detectors. This paper reviews the impact of integrating 4D tracking capabilities on several physics benchmarks both in potential upgrades of the HL-LHC experiments and in several detectors at future colliders, and summarizes the currently available sensor technologies as well as electronics, along with their limitations and directions for R$\&$D.

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arXiv2022

First Measurements on the Timespot1 ASIC: a Fast-Timing, High-Rate Pixel-Matrix Front-End

This work presents the first measurements performed on the Timespot1 ASIC. As the second prototype developed for the TimeSPOT project, the ASIC features a 32x32 channels hybrid-pixel matrix. Targeted to space-time tracking applications in High Energy Physics experiments, the system aims to achieve a time resolution of 30 ps or better at a maximum event rate of 3 MHz per channel with a Data Driven interface. Power consumption can be programmed to range between $1.2W/cm^{2}$ and $2.6W/cm^{2}$. The presented results include a description of the ASIC operation and a first characterization of its performance in terms of time resolution.

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arXiv2021

Accurate modelling of 3D-trench silicon sensor with enhanced timing performance and comparison with test beam measurements

This paper presents the detailed simulation of a double-pixel structure for charged particle detection based on the 3D-trench silicon sensor developed for the TIMESPOT project and a comparison of the simulation results with measurements performed at $π-$M1 beam at PSI laboratory. The simulation is based on the combined use of several software tools (TCAD, GEANT4, TCoDe and TFBoost) which allow to fully design and simulate the device physics response in very short computational time, O(1-100 s) per simulated signal, by exploiting parallel computation using single or multi-thread processors. This allowed to produce large samples of simulated signals, perform detailed studies of the sensor characteristics and make precise comparisons with experimental results.

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arXiv2020

Timing Optimisation and Analysis in the Design of 3D silicon sensors: the TCoDe Simulator

Abstract: Solid state sensors having timing capabilities are becoming an absolute need in particle tracking techniques of future experiments at colliders. In this sense, silicon sensors having 3D structure are becoming an interesting solution, due to their intrinsic speed and radiation resistance. A characteristic of such devices is the strict dependence of their performance on their geometric structure, which can be widely optimised by design, thus requiring suitable tools for an accurate modeling of their behaviour. This paper illustrates the development, performance and use of the TCoDe simulator, specifically dedicated to the fast simulation of carrier transportation phenomena in solid state sensors. Some examples of its effectiveness in the design and analysis of 3D sensors is also given.

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arXiv2020

High-resolution timing electronics for fast pixel sensors

Detectors based on pixels with timing capabilities are gaining increasing importance in the last years. Next-to-come high-energy physics experiments at colliders requires the use of time information in tracking, due to the increasing levels of track densities in the foreseen experimental conditions. Various different developments are ongoing on solid state sensors to gain high-resolution performance at the sensor level, as for example LGAD sensors or 3D sensors. Intrinsic sensor time resolution around 20 ps have been recently obtained. The increasing performance on the sensor side strongly demands an adequate development on the front-end electronics side, which now risks to become the performance bottle-neck in a tracking or vertex-detecting system. This paper aims to analyse the ultimate possible performance in timing of a typically-used front-end circuit, the Trans-Impedance Amplifier, considering different possible circuit configurations. Evidence to the preferable modes of operation in sensor read-out for timing measurement will be given.

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arXiv2020

Intrinsic time resolution of 3D-trench silicon pixels for charged particle detection

In the last years, high-resolution time tagging has emerged as the tool to tackle the problem of high-track density in the detectors of the next generation of experiments at particle colliders. Time resolutions below 50ps and event average repetition rates of tens of MHz on sensor pixels having a pitch of 50$μ$m are typical minimum requirements. This poses an important scientific and technological challenge on the development of particle sensors and processing electronics. The TIMESPOT initiative (which stands for TIME and SPace real-time Operating Tracker) aims at the development of a full prototype detection system suitable for the particle trackers of the next-to-come particle physics experiments. This paper describes the results obtained on the first batch of TIMESPOT silicon sensors, based on a novel 3D MEMS (micro electro-mechanical systems) design. Following this approach, the performance of other ongoing silicon sensor developments has been matched and overcome, while using a technology which is known to be robust against radiation degradation. A time resolution of the order of 20ps has been measured at room temperature suggesting also possible improvements after further optimisations of the front-end electronics processing stage.

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