ABSTRACT
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This work present an analysis of the peculiar characteristics of the front-end electronics for radiation detectors employing bipolar transistors, taking into account the noise, speed and power-dissipation constraints. It is shown that, in... more
This work present an analysis of the peculiar characteristics of the front-end electronics for radiation detectors employing bipolar transistors, taking into account the noise, speed and power-dissipation constraints. It is shown that, in a first approximation, the optimum processing time is inversely proportional to the dissipated power P/sub d/ of the front-end stage, while the optimum noise performance can be made almost independent on P/sub d/. The noise characteristics of a bipolar transistor having a maximum cut-off frequency of 8 GHz have been experimentally determined, and discussed in relation with the low-power requirements. A prototype of a charge amplifier operated with a single power supply of 3 Volt and a dissipation of 600 /spl mu/W has been tested and showed a ENC=470 electrons r.m.s. at 10 ns RC-CR shaping and with a total input capacitance of 6 pF.
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A new electrode geometry for silicon drift chambers is proposed, minimizing the surface of the detector covered with oxide, still maintaining a reasonably high drifting field with no limitation in the det ector size. This Letter describes... more
A new electrode geometry for silicon drift chambers is proposed, minimizing the surface of the detector covered with oxide, still maintaining a reasonably high drifting field with no limitation in the det ector size. This Letter describes the design criteria and discusses the peculiar trajectory of signal electrons within the device. The proposed detector is particularly suited for fine spectroscopy measurements of visible light of soft X-rays, where radiation is totally absorbed within a few microns from the interface.
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This paper describes an experimental setup for spectroscopy measurements based on the digital processing of samples obtained by digitizing the signal pulse as it appears at the output of a proper conditioning circuit. The system shares... more
This paper describes an experimental setup for spectroscopy measurements based on the digital processing of samples obtained by digitizing the signal pulse as it appears at the output of a proper conditioning circuit. The system shares with conventional pulse-height analysis systems the connection to the detector and the preamplifier, but differs from them as it uses an antialiasing filter and a digitizer instead of a shaper and a multichannel analyzer. The implemented algorithm maximizes the signal-to-noise ratio in the estimate of the amplitude of the signal pulse and represents the digital counterpart of the optimum analog processor stated by the theory of the optimum filtering. The system is able to synthesize the best possible filter through the on line measurement of the noises actually present in the experiment, thus leading to the best resolution and allowing a total flexibility in adapting to changeable noise conditions. The performance of the digital system in terms of resolution is investigated and its count rate capability is mentioned. In particular, an improvement in energy resolution of more than 10% has been experimentally achieved with respect to conventional systems based on analog circuitry. All the components of the system are described and, as an example of application, the energy spectrum of 241Am is acquired and reported.
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A charge amplifier, especially designed for FET integrated on silicon radiation detectors, is presented. The circuit is based on the forward biased FET amplifier configuration, which does not require the feedback resistor nor additional... more
A charge amplifier, especially designed for FET integrated on silicon radiation detectors, is presented. The circuit is based on the forward biased FET amplifier configuration, which does not require the feedback resistor nor additional devices for resetting. The severe constraints on the preamplifier design, imposed by the low transconductance of small size integrated FET's, are analyzed as far as loop-gain, bandwidth, and noise are concerned. A circuit topology which satisfies all the requirements even at relatively fast shaping time (1 μs) is proposed and experimentally tested
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CIPHER (Coded Imager and Polarimeter for High Energy Radiation) is a hard X and soft gamma-ray spectroscopic and polarimetric coded mask telescope based on an array of Cadmium Telluride microspectrometers. The position sensitive detector... more
CIPHER (Coded Imager and Polarimeter for High Energy Radiation) is a hard X and soft gamma-ray spectroscopic and polarimetric coded mask telescope based on an array of Cadmium Telluride microspectrometers. The position sensitive detector (PSD) is arranged in 4 modules of 32×32 crystals, each of 2×2 mm2 cross section and 10 mm thickness giving a total active area of about
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The criteria underlying the design of low-noise front-end integrated electronics for radiation and particle detectors have been determined, taking into account the limits in the allowable power dissipation. The analysis specifically... more
The criteria underlying the design of low-noise front-end integrated electronics for radiation and particle detectors have been determined, taking into account the limits in the allowable power dissipation. The analysis specifically treats integrated amplifiers employing silicon bipolar transistors, whose performance has been studied to highlight the ultimate noise limit and the roles of the front-end device parameters such as the
Research Interests: Engineering, Electrical Engineering, Biomedical Engineering, Signal Processing, Low Power, and 11 moreDissipation, Design Criteria, Low Noise, Analog Integrated Circuits, Flicker Noise, Amplifier, Front end, Power Dissipation, Bipolar Transistor, Integrated Circuit Design, and Bipolar Junction Transistor
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ABSTRACT
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We demonstrate a temperature and wavelength shift resilient silicon transmission and routing interconnect system suitable for multi-socket interconnects, utilizing a dual-strategy CLIPP feedback circuitry that safeguards the operating... more
We demonstrate a temperature and wavelength shift resilient silicon transmission and routing interconnect system suitable for multi-socket interconnects, utilizing a dual-strategy CLIPP feedback circuitry that safeguards the operating point of the constituent photonic building blocks along the entire on-chip transmission-multiplexing-routing chain. The control circuit leverages a novel control power-independent and calibration-free locking strategy that exploits the 2nd derivative of ring resonator modulators (RMs) transfer function to lock them close to the point of minimum transmission penalty. The system performance was evaluated on an integrated Silicon Photonics 2-socket demonstrator, enforcing control over a chain of RM-MUX-AWGR resonant structures and stressed against thermal and wavelength shift perturbations. The thermal and wavelength stress tests ranged from 27°C to 36°C and 1309.90 nm to 1310.85 nm and revealed average eye diagrams Q-factor values of 5.8 and 5.9 respecti...
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A low-noise USB-controlled impedance analyzer specifically designed for light monitoring in photonic circuits using contactless waveguide conductance detector (CLIPP) is presented. The on-board microcontroller and auxiliary analog output... more
A low-noise USB-controlled impedance analyzer specifically designed for light monitoring in photonic circuits using contactless waveguide conductance detector (CLIPP) is presented. The on-board microcontroller and auxiliary analog output allow the closed-loop control of photonic components.
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We report on the use of programmable silicon photonic meshes of thermally tuneable interferometers to manipulate dynamically guided-wave and free-space optical beams on a chip through arbitrary linear transformations. Several applications... more
We report on the use of programmable silicon photonic meshes of thermally tuneable interferometers to manipulate dynamically guided-wave and free-space optical beams on a chip through arbitrary linear transformations. Several applications are presented, including automatic reconstruction and unscrambling of mixed optical modes; forming and steering of free-space optical beams; coupling of free-space beams from arbitrary directions of arrival to single-mode waveguides; phase front reconstruction and beaming through scattering media. Automatic self-configuration of the meshes is achieved by exploiting built-in transparent monitors, beam labelling and thermal crosstalk cancellation strategies, enabling scalability to photonic meshes with a large number of interferometers.
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Abstract The paper presents the analog section of a readout electronics for multichannel detector systems using VLSI bipolar technology. The charge amplifier and the fast shaper (peaking time 20 ns) are designed for minimum noise (ENC
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Exploiting a novel channel labeling scheme, we demonstrate automated tuning and locking of a hitless silicon microring-resonator filter. Hitless tuning with more than 30 dB isolation is achieved, enabling application in add-drop... more
Exploiting a novel channel labeling scheme, we demonstrate automated tuning and locking of a hitless silicon microring-resonator filter. Hitless tuning with more than 30 dB isolation is achieved, enabling application in add-drop reconfigurable architectures.
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A mixed-signal electronic system allowing closed-loop control of 16 independent integrated photonic devices equipped with CLIPP transparent optical probes (−35 dBm sensitivity, 50 kHz speed) is presented. It features a 32-channel CMOS... more
A mixed-signal electronic system allowing closed-loop control of 16 independent integrated photonic devices equipped with CLIPP transparent optical probes (−35 dBm sensitivity, 50 kHz speed) is presented. It features a 32-channel CMOS lock-in front-end (203 nV /√Hz noise, 100 dB dynamic range), interfaced via conditioning chains to multiple ADCs and DACs driven by a Xilinx Spartan-6 FPGA for real-time processing, including the generation and demodulation of multiple pilot tones for channel labeling and dithering-based feedback. The results of the platform characterization are reported, along with the first application of automatic control applied to a novel all-optical unscrambler for mode-division multiplexing.
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On-chip optical power monitors are essential elements to calibrate, stabilize, and reconfigure photonic integrated circuits. Many applications require in-line waveguide detectors, where a trade-off has to be found between large... more
On-chip optical power monitors are essential elements to calibrate, stabilize, and reconfigure photonic integrated circuits. Many applications require in-line waveguide detectors, where a trade-off has to be found between large sensitivity and high transparency to the guided light. In this work, we demonstrate a transparent photoconductor integrated on standard low-doped silicon-on-insulator waveguides that reaches a photoconductive gain of more than 106 and an in-line sensitivity as high as −60 dBm. This performance is achieved by compensating the effect of electric charges in the cladding oxide through a bias voltage applied to the chip substrate or locally through a gate electrode on top of the waveguide, allowing one to tune on demand the conductivity of the core to the optimum level.
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We report on the automated control of self-configuring programmable photonics meshes employed for the manipulation of free-space optical beams. Applications include optical beam coupling and identification, phase front correction and... more
We report on the automated control of self-configuring programmable photonics meshes employed for the manipulation of free-space optical beams. Applications include optical beam coupling and identification, phase front correction and transmission through scattering media.
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The complexity scaling up of photonic integrated circuits (PICs) enables the manipulation of many optical signals on a photonic chip, to perform operation like channel (de)multiplexing, routing, and switching. For these applications, it... more
The complexity scaling up of photonic integrated circuits (PICs) enables the manipulation of many optical signals on a photonic chip, to perform operation like channel (de)multiplexing, routing, and switching. For these applications, it is useful to be able to identify each data channel inside the PIC, regardless of the presence of other concurrent channels and optical noise. In this work, we report on the optical signal to noise (OSNR) tolerance of on-chip channel monitoring performed with a transparent detector, namely ContactLess Integrated Photonic Probe (CLIPP) [1], which is integrated in a silicon photonics (SiP) waveguide. We show that, regardless of noise, the CLIPP can measure the power of optical channels that are suitably labelled through a weak modulation tone. An accuracy as high as 0.2 dB is demonstrated for an on-chip OSNR as low as 5 dB/0.1nm, with a power sensitivity of about -28 dBm.
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We present here the first impedance-based characterization of the differentiation process of two human mesencephalic fetal neural stem lines. The two dopaminergic neural stem cell lines used in this study, Lund human mesencephalic... more
We present here the first impedance-based characterization of the differentiation process of two human mesencephalic fetal neural stem lines. The two dopaminergic neural stem cell lines used in this study, Lund human mesencephalic (LUHMES) and human ventral mesencephalic (hVM1 Bcl-XL), have been developed for the study of Parkinsonian pathogenesis and its treatment using cell replacement therapy. We show that if only relying on impedance magnitude analysis, which is by far the most usual approach in, e.g., cytotoxicity evaluation and drug screening applications, one may not be able to distinguish whether the neural stem cells in a population are proliferating or differentiating. However, the presented results highlight that equivalent circuit analysis can provide detailed information on cellular behavior, e.g. simultaneous changes in cell morphology, cell-cell contacts, and cell adhesion during formation of neural projections, which are the fundamental behavioral differences between...
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In this paper, a CMOS monolithic system for the detection through a capacitive measurement of the airborne PM deposited on the surface of the chip is demonstrated. The sensor, whose electrodes are fabricated using the top metal layer of a... more
In this paper, a CMOS monolithic system for the detection through a capacitive measurement of the airborne PM deposited on the surface of the chip is demonstrated. The sensor, whose electrodes are fabricated using the top metal layer of a standard CMOS technology without post-processing steps, features 32 channels with resolution better than 100zF rms that allow a real-time detection, counting and sizing of PM with an equivalent diameter greater than 1μm deposited on the active area of 1.15mm2. The miniaturization and low-power consumption of the resulting system go beyond the state of the art for PM detectors, paving the way to pervasive (smartphone-embeddable) high-performance air quality monitoring and control strategies.
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We present a platform for the feedback control of a multichannel transmitter based on DML sources and a silicon photonic multiplexer and carver circuit. Automatic tuning and wavelength locking are demonstrated in about 150 ms.
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An important region of the electromagnetic spectrum for astrophysics is the hard X- and gamma ray band between 10 keV and a few MeV, where several processes occur in a wide variety of objects and with different spatial distribution and... more
An important region of the electromagnetic spectrum for astrophysics is the hard X- and gamma ray band between 10 keV and a few MeV, where several processes occur in a wide variety of objects and with different spatial distribution and time scales. In order to fulfill the observational requirements in this energy range and taking into account the opportunities given by small/medium size missions (e.g. on the ISS), we have proposed a compact, wide field camera based on a thick (1 cm) position sensitive CdTe detector (PSD). The detector is made of an array of 128×96 CdTe microspectrometers with a pixel size of 2×2 mm2. The basic element of the PSD is the linear module that is an independent detection unit with 32 CdTe crystals and monolithic front-electronics (ASIC) supported by a thin (300 μm) ceramic layer. The expected performance of the PSD over the operative energy range and some of the required ASIC functionality are presented and discussed.
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ABSTRACT
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Coded Imager and Polarimeter for High Energy Radiation (CIPHER) is a hard X- and soft γ- ray spectroscopic and polarimetric coded mask telescope based on an array of Cadmium telluride microspectrometers. The position sensitive detector... more
Coded Imager and Polarimeter for High Energy Radiation (CIPHER) is a hard X- and soft γ- ray spectroscopic and polarimetric coded mask telescope based on an array of Cadmium telluride microspectrometers. The position sensitive detector (PSD) will be arranged in 4 modules of 32×32 crystals, each of 2×2mm2 cross-section and 10 mm thickness giving a total active area of about
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ABSTRACT Since the use of impedance measurements for label-free monitoring of cells has become widespread but still the choice of sensing configuration is not unique though crucial for a quantitative interpretation of data, we demonstrate... more
ABSTRACT Since the use of impedance measurements for label-free monitoring of cells has become widespread but still the choice of sensing configuration is not unique though crucial for a quantitative interpretation of data, we demonstrate the application of a novel custom multipotentiostat platform to study optimal detection strategies. Electrochemical Impedance Spectroscopy (EIS) has been used to monitor and compare adhesion of different cell lines. HeLa cells and 3T3 fibroblasts have been cultured for 12 hours on interdigitated electrode arrays integrated into a tailor-made cell culture platform. Both vertical and coplanar interdigitated sensing configuration approaches have been used and compared on the same cell populations.
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An electrochemical detection system specifically designed for multi-parameter real-time monitoring of stem cell culturing/differentiation in a microfluidic system is presented. It is composed of a very compact 24-channel electronic board,... more
An electrochemical detection system specifically designed for multi-parameter real-time monitoring of stem cell culturing/differentiation in a microfluidic system is presented. It is composed of a very compact 24-channel electronic board, compatible with arrays of microelectrodes and coupled to a microfluidic cell culture system. A versatile data acquisition software enables performing amperometry, cyclic voltammetry and impedance spectroscopy in each of the 12 independent chambers over a 100 kHz bandwidth with current resolution down to 5 pA for 100 ms measuring time. The design of the platform, its realization and experimental characterization are reported, with emphasis on the analysis of impact of input capacitance (i.e., microelectrode size) and microfluidic pump operation on current noise. Programmable sequences of successive injections of analytes (ferricyanide and dopamine) and rinsing buffer solution as well as the impedimetric continuous tracking for seven days of the proliferation of a colony of PC12 cells are successfully demonstrated.
Research Interests: Computer Science, Materials Science, Biomedical Engineering, Microfluidics, Medicine, and 15 moreDopamine, Potentiometry, Computer Systems, Animals, Dielectric Spectroscopy, Capacitance, Microelectrode, Cell Proliferation, Equipment Design, Multielectrode Array, Electrical And Electronic Engineering, Biosensing Techniques, Amperometry, Microfluidic Analytical Techniques, and Cell culture techniques
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ABSTRACT Non-invasive monitoring of silicon microring resonators is demonstrated through a novel contactless integrated photonic probe, which enables multi-point light observation on chip and proves its utility for the tuning and control... more
ABSTRACT Non-invasive monitoring of silicon microring resonators is demonstrated through a novel contactless integrated photonic probe, which enables multi-point light observation on chip and proves its utility for the tuning and control of photonic integrated devices.
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We demonstrate feedback control of silicon microrings by monitoring the light inside the resonators with a Contacless Integrated Photonic Probe (CLIPP), not requiring photon tapping from the waveguide. Tuning, real-time stabilization and... more
We demonstrate feedback control of silicon microrings by monitoring the light inside the resonators with a Contacless Integrated Photonic Probe (CLIPP), not requiring photon tapping from the waveguide. Tuning, real-time stabilization and swapping of the microring resonant wavelengths are shown.
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A compact USB-controlled impedance sensing instrument based on a low-noise analog lock-in detector combined with a pseudo-integrator front-end is presented. This system, whose design is illustrated in this paper along with the results of... more
A compact USB-controlled impedance sensing instrument based on a low-noise analog lock-in detector combined with a pseudo-integrator front-end is presented. This system, whose design is illustrated in this paper along with the results of the experimental characterization, has been custom tailored on a novel application in the field of integrated photonics. Non-invasive light monitoring is achieved by means of the contactless measurement (through a thin dielectric SiO2 cladding) of the variation of the conductivity of a silicon waveguide, with sub-micrometric cross-section, due to propagating infrared light. The instrument measures the sensor impedance up to 10 MHz, featuring a 16 pS conductivity resolution with a 100 ms measuring time. An example of automatic alignment of a source optical fiber to the chip facet achieved with the CLIPP systems is reported.
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A 32channel electronic system for non-invasive light monitoring in integrated photonic circuits with contactless waveguide conductance detector (CLIPP) is presented, featuring 10pS resolution to address multipoint tuning and controlling... more
A 32channel electronic system for non-invasive light monitoring in integrated photonic circuits with contactless waveguide conductance detector (CLIPP) is presented, featuring 10pS resolution to address multipoint tuning and controlling of optical power variations below -30dBm.
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On-chip non-invasive monitoring of WDM-MDM channels transmitted through silicon-photonic waveguides is achieved with a ContactLess Integrated Photonic Probe (CLIPP). Simultaneous monitoring of four intensity-modulated 10 Gbit/s channels... more
On-chip non-invasive monitoring of WDM-MDM channels transmitted through silicon-photonic waveguides is achieved with a ContactLess Integrated Photonic Probe (CLIPP). Simultaneous monitoring of four intensity-modulated 10 Gbit/s channels is demonstrated with no penalty on system performance.
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We demonstrate feedback-control of a thermally actuated silicon microring resonator integrating a transparent light monitor. The microring resonance is locked to the wavelength of an external laser with 150 ms time response.
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We report on our recent achievements on the development of an integrated in-line transparent detector (CLIPP), enabling non-invasive on-chip monitoring of the light and robust feedback controlled schemes for high complexity photonic... more
We report on our recent achievements on the development of an integrated in-line transparent detector (CLIPP), enabling non-invasive on-chip monitoring of the light and robust feedback controlled schemes for high complexity photonic integrated circuits.