"Superconducting radio frequency (SRF) resonators are newly being used in the quantum regime (at temperatures below 1 Kelvin) for integration into 3D quantum computing processing units. The motivation behind these new applications lies in the fact that SRF cavities offer a coherence lifetime that is 1000 times longer than other 2D qubit architectures and provide sensitivities that are orders...
Point Contact Tunneling Spectroscopy (PCTS) is a powerful technique ideal for investigating the surface superconducting properties of materials. Since it utilizes the oxides present on the sample’s surface to probe the superconducting density of states, this tool is valuable for studying devices such as qubits and SRF cavities, where a native or engineered oxide layer is present on the...
To achieve higher acceleration gradients, we are investigating alternatives to classical superconducting niobium cavities. New concepts, such as passivating the high-loss native oxide surface or employing multilayer systems, are promising approaches. Atomic layer deposition (ALD) has proven to be a suitable method for coating the inner surface of a cavity homogeneously and with sub-nanometer...
Multipacting in particle accelerator elements such as drift tubes, superconducting radiofrequency resonating cavities (SRF), couplers… is a major challenge. The multipacting phenomenon is strongly dependent on the surface total electron yield (TEEY) and developing thin film coatings materials to reduce the surface TEEY is of critical importance. In most cases however, the surface dissipation...
To enhance heat-transfer efficiency in SRF cavities, we previously introduced a novel approach that coats the cavity with an inner-wall thermal-conducting film (ITCF). Simulation results showed that ITCF absorbs heat from the RF surface and transmits it to cooler neighbouring regions on the inner wall, thereby reducing the heating-point temperature via an extra heat-transfer route. This work...
This study aims to assess the quality of PEALD-based SIS films and involves several steps to show significant correlations between different measurement results. The growth per cycle is determined by XRR, from which the respective thicknesses of the PEALD-coated thin films are derived. The results are used to determine the London penetration depth λL of a thin superconducting NbTiN layer...
