4,060 research outputs found

    Generic radiation hardened photodiode layouts for deep submicron CMOS image sensor processes

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    Selected radiation hardened photodiode layouts, manufactured in a deep submicron CMOS Image Sensor technology, are irradiated by 60Co gamma-rays up to 2.2 Mrad(SiO2) and studied in order to identify the most efficient structures and the guidelines (recess distance, bias voltage) to follow to make them work efficiently in such technology. To do so, both photodiode arrays and active pixel sensors are used. After 2.2 Mrad(SiO2), the studied sensors are fully functional and most of the radiation hardened photodiodes exhibit radiation induced dark current values more than one order of magnitude lower than the standard photodiode

    Displacement Damage Effects in Pinned Photodiode CMOS Image Sensors

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    This paper investigates the effects of displacement damage in Pinned Photodiode (PPD) CMOS Image Sensors (CIS) using proton and neutron irradiations. The DDD ranges from 12 TeV/g to 1.2times106{1.2 times 10^{6}} TeV/g. Particle fluence up to 5times10145 times 10^{14} n.cm 2^{-2} is investigated to observe electro-optic degradation in harsh environments. The dark current is also investigated and it would appear that it is possible to use the dark current spectroscopy in PPD CIS. The dark current random telegraph signal is also observed and characterized using the maximum transition amplitude

    On the Analysis and Detection of Flames Withan Asynchronous Spiking Image Sensor

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    We have investigated the capabilities of a customasynchronous spiking image sensor operating in the NearInfrared band to study flame radiation emissions, monitortheir transient activity, and detect their presence. Asynchronoussensors have inherent capabilities, i.e., good temporal resolution,high dynamic range, and low data redundancy. This makesthem competitive against infrared (IR) cameras and CMOSframe-based NIR imagers. In this paper, we analyze, discuss,and compare the experimental data measured with our sensoragainst results obtained with conventional devices. A set ofmeasurements have been taken to study the flame emissionlevels and their transient variations. Moreover, a flame detectionalgorithm, adapted to our sensor asynchronous outputs, has beendeveloped. Results show that asynchronous spiking sensors havean excellent potential for flame analysis and monitoring.Universidad de Cádiz PR2016-07Ministerio de Economía y Competitividad TEC2015-66878-C3-1-RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035

    High-speed imaging in fluids

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    High-speed imaging is in popular demand for a broad range of experiments in fluids. It allows for a detailed visualization of the event under study by acquiring a series of image frames captured at high temporal and spatial resolution. This review covers high-speed imaging basics, by defining criteria for high-speed imaging experiments in fluids and to give rule-of-thumbs for a series of cases. It also considers stroboscopic imaging, triggering and illumination, and scaling issues. It provides guidelines for testing and calibration. Ultra high-speed imaging at frame rates exceeding 1 million frames per second is reviewed, and the combination of conventional experiments in fluids techniques with high-speed imaging techniques are discussed. The review is concluded with a high-speed imaging chart, which summarizes criteria for temporal scale and spatial scale and which facilitates the selection of a high-speed imaging system for the applicatio

    Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry

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    We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (<1 m) telescopes capable of precise (<1 mmag) infrared photometry of relatively bright targets. The camera is constructed around the 640x512 pixel APS640C sensor built by FLIR Electro-Optical Components. We designed custom analog-to-digital electronics for maximum stability and minimum noise. The InGaAs dark current halves with every 7 deg C of cooling, and we reduce it to 840 e-/s/pixel (with a pixel-to-pixel variation of +/-200 e-/s/pixel) by cooling the array to -20 deg C. Beyond this point, glow from the readout dominates. The single-sample read noise of 149 e- is reduced to 54 e- through up-the-ramp sampling. Laboratory testing with a star field generated by a lenslet array shows that 2-star differential photometry is possible to a precision of 631 +/-205 ppm (0.68 mmag) hr^-0.5 at a flux of 2.4E4 e-/s. Employing three comparison stars and de-correlating reference signals further improves the precision to 483 +/-161 ppm (0.52 mmag) hr^-0.5. Photometric observations of HD80606 and HD80607 (J=7.7 and 7.8) in the Y band shows that differential photometry to a precision of 415 ppm (0.45 mmag) hr^-0.5 is achieved with an effective telescope aperture of 0.25 m. Next-generation InGaAs detectors should indeed enable Poisson-limited photometry of brighter dwarfs with particular advantage for late-M and L types. In addition, one might acquire near-infrared photometry simultaneously with optical photometry or radial velocity measurements to maximize the return of exoplanet searches with small telescopes.Comment: Accepted to PAS

    New source of random telegraph signal in CMOS image sensors

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    We report a new source of dark current random telegraph signal in CMOS image sensors due to meta-stable Shockley-Read-Hall generation mechanism at oxide interfaces. The role of oxide defects is discriminated thanks to the use of ionizing radiations

    The operational characteristics and potential applications of a low voltage EMCCD in a CMOS process

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    The Electron Multiplying Test Chip 1 (EMTC1) was developed with the aim of creating a device which could produce superior Electron Multiplication (EM) gain at a greatly reduced voltage. An EM gain exceeding 3% per stage has been recorded for a relatively low voltage (~13.0V) from two recently developed pixel structures. An electro-optical characterisation of the EMTC1 is presented focusing on charge transfer via experimental and simulation results aiming to provide insight into the transfer and multiplication process. The Charge Transfer Inefficiency (CTI) is analysed with the aim of providing a greater understanding of the charge transfer process. Light starved applications such as Earth observation and automated inspection are known to benefit from Time Delay Integration (TDI) and electron multiplication. Though traditionally implemented in CCDs, implementing TDI in CMOS technology can lead to an increase of functionality, higher readout speeds and reduced noise. This paper presents a discussion of the implication of these results on the potential applications of this sensor
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