Double beta decay is a powerful tool to investigate the properties of the neutrino and of the weak interaction. Studying characteristics of this decay is very challenging because
of its long half-life and interfering natural backgrounds. One experiment aiming to investigate double beta decay is the COBRA experiment located at the Gran Sasso
Underground Laboratory. COBRA uses room temperature CdZnTe semiconductor detectors that intrinsically contain multiple double beta decay candidates. The previous COBRA Demonstrator had a relatively high background level and thus is not competitive for double beta decay searches. With the objective of reducing the background as well as increasing the signal sensitivity, the experiment was upgraded using large CdZnTe detectors with a novel electrode design.
This work focuses on the study of the new detectors. A pulse shape simulation based on COMSOL and Monte Carlo is developed with the goal of characterizing the new detectors. This simulation framework is also part of a newly developed pulse shape discrimination to suppress background.
Applying those analysis cuts the background index improves by a factor of 23 compared to the previous setup. Furthermore, the 2νββ-decay of 116Cd is investigated using data with an exposure of 0.18 kg·yr. The potential for measuring the excited state transition of this decay is also explored.
Apart from the double beta decay investigations, a study of the charge non-conserving decay of 113Cd will be presented. The new half-life limit helps to constrain the theoretical presumptions for this exotic decay process.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:93494 |
| Date | 29 August 2024 |
| Creators | Chu, Yingjie |
| Contributors | Bemmerer, Daniel, Stekl, Ivan, Zuber, Kai, Technischen Universität Carolo-Wilhelmina zu Braunschweig |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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