Multi Digital Silicon Photon Multipliers (MDSiPM), as image sensors, are utilized to calculate and estimate the properties of the incident light. These properties include spatial location of hits, intensity or number of photons and time of arrival. Some characteristics can be more important than others depending upon the problem at hand. Among endless applications where MDSiPMs are used for, Positron Emission Tomography and LiDAR are the two that this thesis is focused on. Positron Emission Tomography is an imaging technique to monitor functional information about tissue and organs, including early cancer lesions. This constitutes the main difference with structural techniques such as radiography, where, by means of Xrays, a projection of a section of the body under test is obtained. @en

A multipurpose monolithic array of 2×2 multi-channel digital silicon photomultipliers (MD-SiPMs) fabricated in 40nm CMOS technology is presented. Each MD-SiPM comprises 64×64 smart pixels connected to 128 low-power 45ps sliding-scale time-to-digital converters (TDCs). The MD-SiPMs are designed to indirectly capture gamma events in positron emission tomography (PET). The sensor can operate in frame-based and event-driven mode; the latter best suited to capture gamma events. The digital read-out is fully embedded in the sensor and it is reconfigurable by way of serial communication. Data packets are sent following a simple protocol compatible with an external FIFO, therefore eliminating the need of an FPGA. A dedicated input can be used to operate synchronously with an event generator, such as a pulsed laser, useful in other applications, like LiDAR. The system is inherently compatible with 3D-stacking technology; thus serving as a front end for different SPAD technologies, suitable for a variety of applications.

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In time-of-flight (TOF) positron emission tomography (PET), the coincidence resolving time (CRT) has a strong influence on the overall performance. Multichannel digital silicon photomultipliers (MD-SiPMs) are able to obtain several timestamps for gamma photon timemark estimation. Using this feature, the CRT is improved and the system robustness is significantly increased by utilizing multiple photoelectron timestamps. In addition, the PET instrumentation chain is simplified because of the intrinsic digitization and integrated functionality of the MD-SiPM. The main objective of this work is to demonstrate the possibility of building a complete highly-miniaturized PET detector module for endoscopic applications. In addition, we show that it's possible to operate simultaneously several MD-SiPM array chips in order to build a small-animal PET detector modules. We present the implementation of two PET detector modules that are based on MD-SiPMs: a small animal and an endoscopic PET detector modules. The small animal PET detector module consists of 2×4 monolithic MD-SiPM array chips. In addition, this module includes a low-cost field programmable gate array (FPGA), a temperature controlling system and data transfer interfaces. The endoscopic PET detector module comprises a single monolithic array of 9×18 MD-SiPM and a small form-factor FPGA. In this module, a remarkable level of compactness is achieved. Eventually, a thermal characterization and a preliminary radiation measurement are presented.

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