Chockalingam Veerappan

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Image sensors capable of resolving the time-of-arrival (ToA) of individual pho-tons with high resolution are needed in several applications, such as fluores-cence lifetime imaging microscopy (FLIM), Förster resonance energy transfer (FRET), optical rangefinding, and positron emission tomography. In FRET, for example, typical fluorescence lifetime is of the(More)
Abstract–Digital SiPMs in the recent past have emerged as a viable low cost alternative to PMTs providing higher granularity and MRI compatibility. The rich dataset generated by digital SiPM sensors have posed a challenge, especially at the system level when a multitude of such sensors are to be used. In this paper we present a sensor network based(More)
In this paper we illustrate the core technologies at the basis of the European SPADnet project (www., and present the corresponding first results. SPADnet is aimed at a new generation of MRI-compatible, scalable large area image sensors, based on CMOS technology, that are networked to perform gamma-ray detection and coincidence to be used(More)
1 – This paper is the first comprehensive presentation of the SPADnet concept. SPADnet is a fully digital, networked MRI compatible time-of-flight PET system, exploiting the speed and integration density of deep-submicron CMOS technologies. The core enabling technologies of SPADnet are a sensor device comprising an array of 8x16 pixels, each composed of 4(More)
— With the emergence of large arrays of high-functionality pixels, it has become critical to characterize the performance non-uniformity of such arrays. In this paper we characterize a 160x128 array of complex pixels, each with a single-photon avalanche diode (SPAD) and a time-to-digital converter (TDC). A study of the array's non-uniformities in terms of(More)
Medical diagnostics today takes advantage in great part of image sensing and reconstruction techniques. Early detection of several diseases – cancer, in particular – has benefitted from these techniques, thus contributing to save lives and to improve the quality of life of those affected. In this paper we present the first results from the SPADnet project(More)
SPADnet is aimed at a new generation of fully digital, scalable and networked photonic components to enable large area image sensors, with primary target gamma-ray and coincidence detection in (Time-of-Flight) PET. The SPADnet photonic module, which lies at the heart of the concept, is built around an array of tessellated single-photon TSV sensor chips,(More)
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