We investigated the possibility of using several sensing parameters from porous silicon in order to improve gas selectivity. By fabricating porous silicon optical microcavities, three independent ...quantities can be measured, i.e. the electrical conductance, the photoluminescence intensity, and the wavelength of the optical resonance. We monitored the change of these three parameters as a function of NO2 (0.5-5 ppm), ethanol (300-15000 ppm) and relative humidity (0-100%). Preliminary results confirm that the examined species affect the parameters in a different way, both as a relative change and as dynamic.
We designed, produced, and tested RSD (Resistive AC-Coupled Silicon Detectors) devices, an evolution of the standard LGAD (Low-Gain Avalanche Diode) technology where a resistive n-type implant and a ...coupling dielectric layer have been implemented. The first feature works as a resistive sheet, freezing the multiplied charges, while the second one acts as a capacitive coupling for readout pads. We succeeded in the challenging goal of obtaining very fine pitch (50, 100, and 200 μm) while maintaining the signal waveforms suitable for high timing and 4D-tracking performances, as in the standard LGAD-based devices.
Monolithic Active Pixel Sensors (MAPS) are a promising technology that provides large sensitive areas at potentially low power consumption and low material budget. The ARCADIA project is developing ...Fully Depleted MAPS (FD-MAPS) with an innovative sensor design, that uses a backside bias to improve charge collection efficiency and timing over a wide range of operational and environmental conditions. The ARCADIA collaboration has produced a large set of prototypes in the first two engineering runs, with the main design consisting of a 512 × 512 pixel matrix with 25μm pixel pitch and other smaller active sensor arrays. Test structures of pixel matrices with pixel pitches ranging from 10 to 50μm and total thicknesses of 50 to 200μm have also been included, to ease the characterization of the sensors independently from integrated electronics. We give an overview of the status of the project and then focus on the characterization of the passive pixel matrices which include Capacitance–Voltage (CV) and Current–Voltage (IV), as well as Transient Current Technique (TCT) measurements with a red and an infrared laser. We could confirm a single pixel capacitance below 5fF for pixels with 25μm pitch, and a 90% charge collection of MIP-like charge depositions within 12ns in 100μm active thickness. These results are complemented and supported by Technology Computer Aided Design (TCAD) simulations.
This paper presents the principles of operation of Resistive AC-Coupled Silicon Detectors (RSDs) and measurements of the temporal and spatial resolutions using a combined analysis of laser and beam ...test data. RSDs are a new type of n-in-p silicon sensor based on the Low-Gain Avalanche Diode (LGAD) technology, where the n+ implant has been designed to be resistive, and the read-out is obtained via AC-coupling. The truly innovative feature of RSD is that the signal generated by an impinging particle is shared isotropically among multiple read-out pads without the need for floating electrodes or an external magnetic field. Careful tuning of the coupling oxide thickness and the n+ doping profile is at the basis of the successful functioning of this device. Several RSD matrices with different pad width-pitch geometries have been extensively tested with a laser setup in the Laboratory for Innovative Silicon Sensors in Torino, while a smaller set of devices have been tested at the Fermilab Test Beam Facility with a 120 GeV/c proton beam. The measured spatial resolution ranges between 2.5μm for 70–100 pad-pitch geometry and 17μm with 200–500 matrices, a factor of 10 better than what is achievable in binary read-out (binsize∕12). Beam test data show a temporal resolution of ∼40ps for 200 μm pitch devices, in line with the best performances of LGAD sensors at the same gain.
Characterization of FBK SiPMs under illumination with very fast light pulses Tarolli, A.; Dalla Betta, G.-F.; Melchiorri, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
A characterization of the response of SiPMs and SPADs produced at FBK-IRST Trento stimulated with fast laser pulses is presented. The tests were aimed at studying both the intrinsic timing ...proprieties (of SiPMs and SPADs) using the time-correlated single-photon counting technique and the dynamic range (of SiPMs). Measurements were carried out on devices with different cell size, namely, from 40×40 to 100×100
μm
2. Concerning the timing resolution, all the devices exhibit a value less than 150
psec FWHM. The dynamic range of SiPMs shows a response linearity which is in line with the theory describing these devices.
This paper presents the results from the crosstalk and dark count rate (DCR) characterization of a 24 × 72 single photon avalanche diode (SPAD) array, fabricated in a 150 nm CMOS technology. The chip ...under test consists of a dual layer detection system developed in view of applications to charged particle tracking. A three step procedure, used for the crosstalk characterization, is presented. The crosstalk probability, taking place in 5 × 5 sub arrays built around noisy pixels, has been computed. Eventually, random telegraph signal (RTS) fluctuations in DCR, at different bias conditions, are briefly discussed.
Design optimization of ultra-fast silicon detectors Cartiglia, N.; Arcidiacono, R.; Baselga, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2015, Letnik:
796
Journal Article
Recenzirano
Odprti dostop
Low-Gain Avalanche Diodes (LGAD) are silicon detectors with output signals that are about a factor of 10 larger than those of traditional sensors. In this paper we analyze how the design of LGAD can ...be optimized to exploit their increased output signal to reach optimum timing performances. Our simulations show that these sensors, the so-called Ultra-Fast Silicon Detectors (UFSD), will be able to reach a time resolution factor of 10 better than that of traditional silicon sensors.
Novel strategies for fine-segmented Low Gain Avalanche Diodes Paternoster, G.; Borghi, G.; Arcidiacono, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2021, Letnik:
987
Journal Article
Recenzirano
Low Gain Avalanche Diodes (LGADs) are now considered a viable solution for 4D-tracking thanks to their excellent time resolution and good resistance to high radiation fluence. However, the currently ...available LGAD technology is well suited only for applications that require coarse space precision, pixels with pitch in the range 500µm–1mm, due to the presence of a no-gain region between adjacent pixels of about 50μm, in which the gain is completely suppressed. In this paper, we will discuss the segmentation issues in the LGAD technology and we will present two new segmentation strategies aimed at producing LGADs with high spatial resolution and high fill factor. The first presented design is the so-called Trench-Isolated LGAD (TI-LGAD). Here, the pixel isolation is provided by trenches, physically etched in the silicon and then filled with silicon oxide. The second design is the Resistive AC-coupled Silicon Detector (RSD), an evolution of LGADs, where the segmentation is obtained by means of AC-coupled electrodes. Prototypes of both designs have been produced at FBK and characterized at the Laboratories for Innovative Silicon Sensors (INFN and University of Turin) by means of a laser setup to estimate the space resolution and the fill factor. The functional characterization shows that both the technologies yield fully working small pixel LGADs (down to 50µm), providing the first examples of sensors able to concurrently measure space and time with excellent precision.
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.
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