[ca] ATLAS és un dels dos experiments de propòsit general del Large Hadron Collider (LHC) que utilitza la tecnologia del calorímetre per mesurar l'energia d'una partícula quan passa pel detector. Els sistemes de calorímetres de l'experiment ATLAS van funcionar amb èxit durant l'execució 1 i 2 del període de presa de dades de l'LHC. Al capítol 4 es presenta una discussió detallada dels experiments de LHC i ATLAS. El capítol 2 i el capítol 3 d'aquesta tesi estan dedicats a la introducció general als calorimetres i la calorimetria. Aquest treball de tesi se centra en l'anàlisi de les dades de calibratge Run-2 recollides amb el calorimetre de rajoles hadrònics ATLAS. El calorímetre hadrònic Tile (TileCal), descrit amb detall al capítol 5, és un dels dos components del sistema de calorimetria ATLAS que mesura l'energia de les partícules hadròniques i és la part més pesada de l'experiment ATLAS. El Tile Calorimeter utilitza quatre sistemes de calibratge dedicats principals per fer un seguiment del rendiment dels diferents components del detector en cada etapa de la reconstrucció del senyal TileCal. Al capítol 6 es proporciona una discussió més detallada sobre els sistemes de calibratge. mesura (amplificació, eficiència quàntica, eficiència del fotocàtode, guany, corrent fosc, linealitat i estabilitat). El disseny tècnic i els resultats inicials de les proves d'alguns PMT obtinguts amb el banc de proves del CERN es resumeixen al capítol 9. Finalment, la conclusió s'extreu al capítol 10.

[en] ATLAS is one of the two general-purpose experiments at the Large Hadron Collider (LHC) which uses calorimeter technology to measure the energy of a particle as it passes through the detector. The ATLAS experiment calorimeter systems operated successfully during Run-1 and Run-2 of the LHC data-taking period. A detailed discussion of LHC and ATLAS experiments is given in Chapter 4. Chapter 2 and Chapter 3 of this dissertation are dedicated to the general introduction to calorimeters and calorimetry. This dissertation work focuses on the analysis of the Run-2 calibration data collected with the ATLAS hadronic Tile Calorimeter. The Tile hadronic Calorimeter (TileCal), described in detail in Chapter 5, is one of the two components of the ATLAS calorimetry system which measures the energy of the hadronic particles and is the heaviest part of the ATLAS experiment. The Tile Calorimeter uses four main dedicated calibration systems to track the performance of the various detector components at each stage of the TileCal signal reconstruction. A more detailed discussion on calibration systems is given in Chapter 6. The laser Calibration system is one of the four systems which calibrate and monitors the 9852 photomultiplier tubes (PMTs) and detector readout electronics. The determination of the PMT response variation with the Laser system and the data analysis methods are detailed in Chapter 7. Finally, the description of the calibration procedure and the observed PMT response drifts during LHC Run-2 using laser calibration data are also discussed. During the development of this dissertation, all the results shown in this chapter were discussed and approved by the TileCal group as ATLAS TileCal public results. The results presented here are also a part of the TileCal internal note that is an input for a publication in preparation. A part of this work was also shown in a poster at LHCC 2020 poster session which was held on 19th Feb 2020. Chapter 8 of this dissertation is divided into three main sections highlighting the results of the modeling of PMT response evolution. The response of the photomultiplier tubes depends on its past operation, the amount of light collected, and the current delivered in hours, days, and weeks prior to its current use. The first section discusses the different approaches that were made during this dissertation work to quantify the response recovery of the PMTs during each Year End Technical Stops (YETS) period of Run-2. The second section focuses on the different models studied to better understand the PMT response evolution including the response recovery as well as response loss as a function of machine Luminosity convoluted function. In the final and last section, the results of the model of Run-2 PMT response evolution as a luminosity convoluted function are used to predict the future PMT response evolution in Run-3 and Run-4 when the LHC will deliver higher luminosities, leading to even more significant trends in the photomultipliers responses. All the results shown in this chapter were shown and discussed in several internal TileCal meetings as well as in TileCal Calibration, Data Preparation, and Performance session during Tile Week. In the future, the Tile calorimeter will be equipped with 1000 new PMTs, so three test benches, one of them at CERN, have been developed in order to fully qualify all PMTs. The performances of this test bench are inspected for each type of measurement (amplification, quantum efficiency, photocathode efficiency, gain, dark current, linearity, and stability). The technical design and initial test results of some PMTs obtained with the CERN test bench are summarized in chapter 9.