The basic principle of operation of silicon sensors with resistive read-out is built-in charge sharing. Resistive Silicon Detectors (RSD, also known as AC-LGAD), exploiting the signals seen on the ...electrodes surrounding the impact point, achieve excellent space and time resolutions even with very large pixels. In this paper, a TCT system using a 1064 nm picosecond laser is used to characterize RSD sensors produced by Fondazione Bruno Kessler. The paper first introduces the parametrization of the errors in the determination of the position and time coordinates in RSD, then outlines the reconstruction method, and finally presents the results. Three different pixel pitches are used in the analysis: 200 × 340, 450 × 450, and 1300 × 1300 μm2. At gain = 30, the 450 × 450 μm2 pixel achieves a time jitter of 20 ps and a spatial resolution of 15 μm concurrently, while the 1300 × 1300 μm2 pixel achieves 30 ps and 30 μm, respectively. The implementation of cross-shaped electrodes improves considerably the response uniformity over the pixel surface.
Design optimization of the UFSD inter-pad region Siviero, F.; Arcidiacono, R.; Borghi, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
April 2024, 2024-04-00, 2024-04-01, Letnik:
1061, Številka:
C
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This paper reports on a measurement campaign to characterize the inter-pad region of Ultra-Fast Silicon Detectors (UFSDs) manufactured by Fondazione Bruno Kessler. The devices under test are either ...pixel or strip arrays, featuring a large number of different inter-pad layouts; both pre-irradiation and irradiated sensors have been measured. The aim of the study is to link the design parameters of the inter-pad region to the operation of the sensors, providing insights into the design of UFSD arrays with narrow inter-pad gaps. We concluded that, in the UFSD design, the doping level and the area of the p-stop should be kept low, in order to avoid the early breakdown of the device and the micro-discharges effect; UFSDs with such characteristics proved also rather insensitive to floating pads and irradiation. Thanks to these findings, it was possible to design a UFSD array that yields the expected performance with an inter-pad width as small as 25 μm, significantly improving its fill factor with respect to standard designs. Two innovative experimental techniques are presented in this work: the first one is based on a TCT setup, the second makes use of an ultra-low light CCD camera.
DC-coupled resistive silicon detectors for 4D tracking Menzio, L.; Arcidiacono, R.; Borghi, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2022, Letnik:
1041
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In this work, we introduce a new design concept: the DC-coupled Resistive Silicon Detectors, based on the LGAD technology. This new design intends to address a few known drawbacks of the first ...generation of AC-coupled Resistive Silicon Detectors (RSD). The sensor behaviour is simulated using a fast hybrid approach based on a combination of two packages, Weightfield2 and LTSpice. The simulation demonstrates that the key features of the RSD design are maintained, yielding excellent space and time resolutions: a few tens of ps and a few microns. In this report, we will outline the optimization methodology and the results of the simulation. We will also present detailed studies on the effects induced by the choice of key design parameters on the space and time resolutions provided by this sensor.
The growing interest on the use of colloidal Quantum Dots (QDs) in scintillation and dosimetry applications in comparison with organic fluorophores relies in their narrower and tunable ...photoluminescence (PL) emission, easier chemical processability and higher cross-section for ionizing radiation. In this context, a deep understanding of the role of the embedding medium on the QD optical properties in unirradiated and irradiated samples represents an important issue. In this paper, we present the optical characterization of colloidal core-shell CdSe/ZnS QDs embedded in polyvinyl alcohol (PVOH) and irradiated with 2 MeV protons at different fluences. The characterization of the samples, performed by both steady-state and time-resolved PL measurements, indicates a damage of the QDs at the lowest fluence (1013 H+cm−2), demonstrated by a quenching of the QD PL intensity and by a shortening of the QD lifetime. At the middle fluence (5 × 1013 H+cm−2) a partial recovering of the QD optical properties are observed, due to energy transfer phenomena between radiation-induced PL defects in the PVOH, acting as donors, and the QDs, acting as acceptors. The higher concentration of PVOH PL defects in the most irradiated sample (1014 H+cm−2) led to an enhancement of the QD PL intensity in comparison with the unirradiated sample, highlighting the crucial role of the embedding medium in the post-irradiation QD optical response.
•The QD embedding medium has an important role on the irradiated QD optical response.•At the fluence of 1013 H+cm−2, QD PL intensity and lifetime decrease.•At the fluence of 5 × 1013 H+cm−2, QD PL intensity and lifetime are partly recovered.•At the fluence of 1014 H+cm−2, QD PL intensity and lifetime are enhanced.•Energy transfer phenomena arise between PVOH photoluminescent defects and QDs.
A CMOS 3-D Imager Based on Single Photon Avalanche Diode Stoppa, D.; Pancheri, L.; Scandiuzzo, M. ...
IEEE transactions on circuits and systems. I, Regular papers,
2007-Jan., 20070101, Letnik:
54, Številka:
1
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A 64-pixel linear array aimed at 3-D vision applications is implemented in a high-voltage 0.8 mum CMOS technology. The detection of the incident light signals is performed using photodiodes biased ...above breakdown voltage so that an extremely high sensitivity can be achieved exploiting the intrinsic multiplication effect of the avalanche phenomenon. Each 38times180-mum 2 pixel includes, besides the single photon avalanche diode, a dedicated read-out circuit for the arrival-time estimation of incident light pulses. To increase the distance measurement resolution a multiple pulse measurement is used, extracting the mean value of the light pulse arrival-time directly in each pixel; this innovative approach dramatically reduces the dead-time of the pixel read-out, allowing a high frame rate imaging to be achieved. The sensor array provides a range map from 2 m to 5 m with a precision better than plusmn0.75% without any external averaging operation. Moreover, with the same chip, we have explored for the first time the implementation of an indirect time-of-flight measurement by operating the proposed active pixel in the photon counting mode
State-of-the-art and evolution of UFSD sensors design at FBK Arcidiacono, R.; Borghi, G.; Boscardin, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2020, Letnik:
978, Številka:
C
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In the past few years, there has been growing interest in the development of silicon sensors able to simultaneously measure accurately the time of passage and the position of impinging charged ...particles. In this contribution, a review of the progresses in the design of UFSD (Ultra-Fast Silicon Detectors) sensors, manufactured at the FBK (Fondazione Bruno Kessler) Foundry, aiming at tracking charged particles in 4 dimensions, is presented. The state-of-the-art UFSD sensors, with excellent timing capability, are planned to be used in both ATLAS and CMS experiments detector upgrade, in order to reduce the background due to the presence of overlapping events in the same bunch crossing.
The latest results on sensors characterization including time resolution, radiation resistance and uniformity of the response are here summarized, pointing out the interplay between the design of the gain layer and the UFSD performances. The research is now focusing on the maximization of the sensor fill factor, to be able to reduce the pixel size, exploring the implementation of shallow trenches for the pixel isolation and the development of resistive AC-coupled UFSD sensors. In conclusion, a brief review on research paths tailored for detection of low energy X-rays or for low material budget applications is given.
Optimization of the gain layer design of ultra-fast silicon detectors Siviero, F.; Arcidiacono, R.; Borghi, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2022, Letnik:
1033
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In the past few years, the need of measuring accurately the spatial and temporal coordinates of the particles generated in high-energy physics experiments has spurred a strong R&D in the field of ...silicon sensors. Within these research activities, the so-called Ultra-Fast Silicon Detectors (UFSDs), silicon sensors optimized for timing based on the Low-Gain Avalanche Diode (LGAD) design, have been proposed and adopted by the CMS and ATLAS collaborations for their respective timing layers. The defining feature of the Ultra-Fast Silicon Detectors (UFSDs) is the internal multiplication mechanism, determined by the gain layer design. In this paper, the performances of several types of gain layers, measured with a telescope instrumented with a 90Sr β-source, are reported and compared. The measured sensors are produced by Fondazione Bruno Kessler (FBK) and Hamamatsu Photonics (HPK).
The sensor yielding the best performance, both when new and irradiated, is an FBK 45 μm-thick sensor with a carbonated deep gain implant, where the carbon and the boron implants are annealed concurrently with a low thermal load. This sensor is able to achieve a time resolution of 40 ps up to a radiation fluence of 2.5⋅1015 neq/cm2, delivering at least 5 fC of charge.
Porous silicon (PS) conductometric gas sensors can exhibit large sensitivity to gases, due to the large surface versus volume ratio of porous silicon. A possible application is the detection of ...traces of nitrogen dioxide (NO2), an air pollutant. Delta G/G signals in excess of 10 in the presence of concentrations as low as 50 ppb in dry air can be demonstrated. Unfortunately, such high sensitivity to NO2 is achieved, in fresh samples, with poor reversibility. Another problem is the interference of water vapor, which also affects the porous silicon conductivity. However, we show that reversibility is complete in aged samples, and sensitivity to water vapor is lowered. Although in aged samples large Delta G/G signals are harder to achieve, we show that concentration levels of NO2 at few tens of ppb are still detectable.
Tracking in 4 dimensions Cartiglia, N.; Arcidiacono, R.; Baldassarri, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2017, Letnik:
845, Številka:
C
Journal Article
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In this contribution we will review the progresses toward the construction of a tracking system able to measure the passage of charged particles with a combined precision of ∼10ps and ∼10μm, either ...using a single type of sensor, able to concurrently measure position and time, or a combination of position and time sensors.
Two different Single-Photon Avalanche Diode (SPAD) structures in a standard 0.15-nm CMOS technology are presented. A characterization of the two detectors, having a 10-μm active-area diameter, and ...monolithically integrated with a passive quenching circuit and a fast comparator is presented. The two devices exhibit respectively a typical dark count rate of 230cps and 160cps, an afterpulsing probability of 2.1% and 1.3% at 30ns dead time, a Photon Detection Probability of 31% and 26 % at λ=470nm and a timing resolution of 170ps and 60ps. The adopted technology is therefore promising for the realization of SPAD-based image sensors with good overall performance.
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