Erilliskomponenttiresonaattori hermeettisessä kaviteetissa

As quantum computing advances towards practical implementation, preserving coherence in superconducting circuits remains a central challenge in developing scalable systems. Advances in materials science and fabrication techniques have significantly improved component quality over the past decade. In particular, treatments such as chemical etching and protective coatings have demonstrated reductions in two-level system (TLS) losses by reducing oxide-related dissipation. However, these methods are insufficient to prevent re-oxidation when devices are exposed to the atmosphere between fabrication and measurement, introducing decoherence channels and hindering reproducibility across cooldown cycles. This thesis addresses these issues by fabricating and evaluating a hermetically sealed three-dimensional aluminum cavity capable of preserving vacuum and preventing oxidation during cooldown cycling. We begin by fabricating the cavity, after which we test its vacuum integrity using a helium leak detector and its structural integrity under repeated thermal changes. After this, we characterize test samples and assess the cavity’s suitability for standardized quality factor and two-level system loss measurements. The results show that the cavity remains sealed across varying temperatures and supports reliable characterization measurements. These results demonstrate that hermetically sealed cavities present a promising strategy for reducing decoherence and improving the reproducibility of superconducting qubit experiments, although further research is warranted to evaluate the long-term viability of the device.