Installation, development, debugging of systems and data analysis of the upgraded New Small Wheel Detector of the Atlas experiment at CERN

Abstract

This thesis focuses on the operation and debugging of MicroMegas detectors for the New Small Wheel (NSW) experiment at CERN during their commissioning period. The New Small Wheel is one of the upgrades for the ATLAS detector to meet the increased energy and luminosity demands of the Large Hadron Collider (LHC), achieved through the use of MicroMegas and small Strip Thin-Gap Chamber (sTGC) technologies. It was built to replace the outdated Small Wheel detector, which did not meet the necessary specifications for Run-3 of the LHC. Through this dissertation, a complete picture of the authors' daily routine during the commissioning phase in building B191 is given, so that readers can understand the problems they faced and the methodology that they developed for faster and optimal problem-solving, taking into account the strict deadlines under which the ATLAS upgrades were carried out. In the context of this thesis, there were significant issues with the service systems of the MicroMegas detectors of the NSW technology. Specifically, issues are covered around the debugging of low-voltage systems of MicroMegas detectors, during which mainly issues of noise, communication between subsystems, power supply, and others were addressed, with the ultimate goal of ensuring the smooth operation of the NSW detectors during the LHC's Run-3. All stages of testing, debugging, assembly, and placement of detectors on the New Small Wheel wheels are described. The methods and tests used to determine the correct operation and performance of the MicroMegas detectors are also described in detail, including a description of the issues that arose during the authors' work at the ATLAS experiment at CERN and how they were addressed. Various tests were used to determine performance, providing an overall picture of the levels of intrinsic noise. These tests and the way they work is described in detail and also an explanation of how they help the commissioning team is given. The process followed to place the New Small Wheel detectors in their final position, located in the end-cap toroids of the ATLAS at Point 1 of the LHC, is also described. The verification process of their operation is analysed, similar to the one followed in building B191, as well as the peculiarities that arise in these tasks due to the morphology of Point 1. Finally, there is a reference to the problems encountered there and the issues that remain unresolved