Radiation resistant LGAD design Ferrero, M.; Arcidiacono, R.; Barozzi, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2019, Letnik:
919
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In this paper, we report on the radiation resistance of 50-micron thick Low Gain Avalanche Diodes (LGAD) manufactured at the Fondazione Bruno Kessler (FBK) employing different dopings in the gain ...layer. LGADs with a gain layer made of Boron, Boron low-diffusion, Gallium, Carbonated Boron and Carbonated Gallium have been designed and successfully produced at FBK. These sensors have been exposed to neutron fluences up to ϕn∼3⋅1016n∕cm2 and to proton fluences up to ϕp∼9⋅1015p∕cm2 to test their radiation resistance. The experimental results show that Gallium-doped LGAD are more heavily affected by the initial acceptor removal mechanism than those doped with Boron, while the addition of Carbon reduces this effect both for Gallium and Boron doping. The Boron low-diffusion gain layer shows a higher radiation resistance than that of standard Boron implant, indicating a dependence of the initial acceptor removal mechanism upon the implant density.
First FBK production of 50 μm ultra-fast silicon detectors Sola, V.; Arcidiacono, R.; Boscardin, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2019, Letnik:
924
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Fondazione Bruno Kessler (FBK, Trento, Italy) has recently delivered its first 50 μm thick production of Ultra-Fast Silicon Detectors (UFSD), based on the Low-Gain Avalanche Diode design. These ...sensors use high resistivity Si-on-Si substrates, and have a variety of gain layer doping profiles and designs based on Boron, Gallium, Carbonated Boron and Carbonated Gallium to obtain a controlled multiplication mechanism. Such variety of gain layers will allow identifying the most radiation hard technology to be employed in the production of UFSD, to extend their radiation resistance beyond the current limit of ϕ∼ 1015 neq/cm2. In this paper, we present the characterisation, the timing performance, and the results on radiation damage tolerance of this new FBK production.
In this paper we present the numerical simulation of silicon detectors with internal gain as the main tool for 4-dimensional (4D) particle trackers design and optimization. The Low-Gain Avalanche ...Diode (LGAD) technology and its present limitations are reviewed with the aim of introducing the Resistive AC-Coupled Silicon Detectors (RSD) paradigm as a case study of our investigation. Authors here present Spice-like and 2D/3D Technological Computer-Aided Design (TCAD) simulations to characterize sensors in terms of both their electrostatic behavior, capacitive (dynamic) coupling and radiation-hardness performances, showing the methodological approach used in order to extract the set of layout rules allowing the release of RSD1, the incoming production run at Fondazione Bruno Kessler (FBK) of next-generation silicon detectors for 4D tracking with intrinsic 100% fill-factor.
A single-photon avalanche diode-based pixel array for the analysis of fluorescence phenomena is presented. Each 180 times 150 - mum 2 pixel integrates a single photon detector combined with an active ...quenching circuit and a 17-bit digital events counter. On-chip master logic provides the digital control phases required by the pixel array with a full programmability of the main timing synchronisms. The pixel exhibits an average dark count rate of 3 kcps and a dynamic range of over 120-dB in time uncorrelated operation. A complete characterization of the single photon avalanche diode characteristics is reported. Time-resolved fluorescence measurements have been demonstrated by detecting the fluorescence decay of quantum-dot samples without the aid of any optical filters for excitation laser light cutoff.
In scintillation and dosimetry applications, the increasing interest on the use of colloidal quantum dots (QDs) in comparison with organic fluorophores is mainly due to their easier chemical ...processability, narrower photoluminescence (PL) emission, and higher cross-section for ionizing radiation. The development of scintillators and dosimeter based on QDs, however, relies on a deep understanding of the effects of ionizing radiation on QD structures. In this paper, we present the optical characterization of colloidal cadmium-free InGaP/ZnS core–shell QDs embedded in polydimethylsiloxane (PDMS) and irradiated with 2 MeV protons (H+) in the fluence range of 1014 to 1015 H+ cm–2. Steady-state PL measurements of the irradiated samples show a decrease of the average QD PL intensity, indicating the introduction of PL quenching centers. Time-resolved PL measurements, acquired with a time-correlated single photon counting system, provide a way to probe the radiation-induced change in the carrier recombination dynamics of the QDs. A detailed analysis of the time-resolved PL curves demonstrates the presence of PL quenching defects localized both at the inner (core) and at the outer (shell) structure of the nanocrystal. The radiation-induced change in the QD optical properties, coupled with a suitable radiation hardness of the PDMS in these irradiation conditions, open the way for possible future applications related to dosimetry systems based on QDs as nanostructured sensing elements.
Single-photon avalanche diode (SPAD) arrays fabricated in a 180-nm CMOS technology with a high-voltage option have been exposed to calibrated neutron and X-ray sources to evaluate their radiation ...tolerance. The technology is being investigated in view of the design of low material budget detectors for charged particle tracking based on the coincidence of the signals coming from two or more overlapping layers of SPAD sensors. Each element in the array is a monolithic detector including the processing electronics together with the diode in the same substrate. Different sensor dimensions and structures have been implemented in the test chip to thoroughly explore the technology features. This paper will present and discuss the results from the characterization, in terms of dark count rate, of SPAD arrays irradiated with X-ray doses reaching 1 Mrad(SiO 2 ) and with neutron fluences up to <inline-formula> <tex-math notation="LaTeX">10^{11}~1 </tex-math></inline-formula>-MeV neutron equivalent cm<inline-formula> <tex-math notation="LaTeX">^{-2} </tex-math></inline-formula>.
Single-photon avalanche diodes (SPADs) fabricated using two different CMOS technologies were exposed to a neutron source up to a maximum fluence of <inline-formula> <tex-math notation="LaTeX">3\times ...10^{11}\,\,1 </tex-math></inline-formula>-MeV neutron equivalent cm −2 . Significant changes in the dark count rate (DCR), with a strong dependence on the fluence and the device active area, were detected after irradiation. A model for the probability of DCR degradation, accounting for the source spectrum and the geometry of the device under test (DUT), was proposed and proved to be in good agreement with experimental data. The model may be helpful in performing worst-case analysis of SPAD-based detection systems under neutron irradiation.
Dark count rate (DCR) increase in CMOS single-photon avalanche diodes (SPADs) exposed to a nonmonochromatic neutron source is modeled, taking into accountthe source spectrum and the geometry of the ...device under test. Experimental results from the characterization of SPADs fabricated in a 150-nm technology and irradiated with 1-MeV neutron equivalent fluences up to 1011 cm-2 are found to be in good agreement with the theoretically calculated distribution of the nonionizing energy deposited in the device substrate.
Fully depleted monolithic active pixel sensors (FD-MAPSs) represent a state-of-the-art detector technology and profit from a low material budget and cost for high-energy physics experiments and other ...fields of research like medical imaging and astro-particle physics. Compared to the MAPS currently in use, fully depleted pixel sensors have the advantage of charge collection by drift, which enables a fast and uniform response overall to the pixel matrix. The functionality of these devices has been shown in previous proof-of-concept productions. In this article, we describe the optimization of the test pixel designs that will be implemented in the first engineering run of the demonstrator chip of the ARCADIA project. These optimization procedures include radiation damage models that have been employed in Technology Computer Aided Design simulations to predict the sensors’ behavior in different working environments.