AbstractsEngineering

The aim of this thesis is to present a solution for the readout of Silicon Photo-Multipliers (SiPMs) arrays improving currently implemented systems. Using as a starting point previous designs with similar objectives a novel current mode input stage has been designed and tested. To start with the design a valid model has been used to generate realistic output from the SiPMs depending on light input. Design has been performed in first place focusing in general applications for medical imaging Positron Emission Tomography (PET) and then using the same topology for a more constrained design in particle detectors (upgrade of Tracker detector at LHCb experiment). A 16 channel ASIC for PET applications including the novel input stage has demonstrated an excellent timing measurement with good energy resolution measurement and pile-up detection. This document starts with the analysis of the requirements needed to fit such a system, followed by a detailed description of the input stage and analog processing. Signal is divided in the input stage into three different signal paths: timing, energy and pileup. Every channel performs different signal analysis to deliver; a fast time signal output (digital edge), energy output (a linear time over threshold digital output) and a digital bit to signal pile-up. The time information is then ORed between all channels to generate a single timing output. All the pile-up bits are combined in a digital word ready to be readout for the 16 channels. Design has been optimized for reduced power consumption and no components needed to interface inputs and outputs. Digital slow control to tune the circuit behaviour is also included. The prototype measurements have proved to be a valid option for integration in a full system scanner. An adapted prototype of the input stage using different technology and adapted to the different constraints from a particle detector is also presented. Only simulation results are available since device is still under production. An analysis of the different requirements needed by the SciFi tracker design is summarized. Current specifications are still evolving since final sensor is still not defined, but other requirements and some tunable elements permits to design such prototypes.; L’objectiu d’aquesta tesi és presentar una solució per a la lectura de matrius de fotomultiplicadors de silici (SiPM) millorant les característiques de sistemes actuals. Amb aquesta finalitat s’ha dissenyat i provat el circuit d’una nova etapa d’entrada. En primer lloc s’ha dissenyat pensant en aplicacions genèriques i per a imatge mèdica, concretament per a escàners PET (Positron Emission Tomography). Però més endavant s’aplica la mateixa topologia per a una aplicació més concreta i específica com és un detector de partícules (l’actualització del Tracker a l’experiment LHCb). Els SiPM són uns dispositius electrònics relativament nous amb la possibilitat de comptar fotons i millorant algunes característiques dels sensors actuals, com serien la tensió d’operació més baixa, més guany o…