Development of Quality Assurance Methods for Particle Detectors

Abstract

The purpose of this thesis is to develop, establish and apply novel quality assurance (QA) methods for nuclear and high-energy physics particle detectors. The detectors should be maintenance-free since devices can only be replaced during long technical shut-downs. Furthermore, the detector modules must endure handling during installation and withstand heat generation and cooling during operations. Longevity in a severe radiation environment must also be assured. Visual inspection and electrical characterisation of particle detectors are presented in this work.

The detector studies included in this thesis, while based on different technologies, were united by the demand for reliable and enduring particle detectors. Four major achievements were accomplished during the the Gas Electron Multiplier (GEM) foil studies: a software analysis capable of precise foil inspection was developed, a rigorous calibration procedure for the Optical Scanning System was established, a detailed 3D GEM foil hole geometry study was performed for the first time and an impact of the hole geometry on the detector gain was confirmed. Promising results were also achieved during the solid-state detectors studies. A new technique for assuring the height uniformity of the chip interconnections in the pixel detector modules was proposed and implemented. Two semiconductor detectors (Si and GaAs) were designed, microfabricated and tested. The consistency of the QA results demonstrated the detectors reliability and preparedness to serve the needs of future particle and nuclear physics experiments.

During the performed studies, strict calibration techniques and measurement uncertainties were applied to guarantee the trustworthy accuracy of the used measurement tools. Thus, all quality assurance techniques presented in this thesis were held in clean conditions at monitored temperature and humidity.

The combined results of this thesis demonstrate the importance of adequate quality assurance for guaranteed accurate data collection and long operating life of the detector.

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