Light yield studies of neutron irradiated plastic scintillators and the testing of the front-end readout system of the Atlas tile calorimeter
Date
2020
Authors
Masuku, Thabo
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Abstract
The CERN’s Large Hadron Collider (LHC) is the largest particle accelerator in the World. This comprises a variety of experiments to investigate the basic structure of matter in the universe. A Toroidal LHC Apparatus (ATLAS) is one of the experiments at CERN that is used to detect particles that result from the proton-proton collisions. The ATLAS detector is a general-purpose detector. During the maintenance periods, the ATLAS Tile Calorimeter (TileCal) detector modules are repaired/fixed. The Front-End (FE) electronics of these TileCal modules are tested and maintained using the MobiDICK system and if they are faulty they are repaired or replaced. The FE readout system, which is housed in the super-drawers, is testedand verified using the MobiDICK system. The upgrade of the LHC to the High-Luminosity LHC (HL-LHC) will provide great opportunities to explore new physics beyond the Standard Model. This poses significant challenges to the detector and the Trigger and data acquisition system (TDAQ). The TileCal readout electronics will be replaced during the Phase-II upgrade to cope with the HL-LHC’s increased luminosity. In this study we focus on the certification of the Demonstrator at the particle test beams. The Demonstrator’s latest electronics are being commissioned to be integrated into ATLAS during the LS2. This study presents the early readout certification of the Demonstrator. Due to their properties, such as fast time response and high optical transmission, plastic scintillators are used in particle detectors. The fast pulse generation allows for fast readout, and the intensity of the light is proportional to the energy deposit. Scintillators are used to measure energies and to reconstruct the particles’ path through the luminescence process due to ionizing radiation. However, long exposure to ionizing radiation can cause permanent damage to the scintillators. In this study we focus on the effects of neutron irradiation of plastic scintillators similar to that of the lifetime of the HL-LHC. The plastic scintillator being investigated are the UPS-923A blue scintillators and green scintillators. The optical properties of the irradiated samples are studied using the techniques of light yield measurements
Description
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science, 2020