Description
Conventional PVD, energetic condensation from highly ionized plasmas (HiPIMS, Arc Deposition, ECR plasma deposition …), CVD...
The SRF cavities made with a niobium coating on a copper substrate (Nb/Cu) offer several advantages over those made with bulk niobium. This is mainly attributed to the excellent thermal properties of copper, enabling operation at higher temperatures and consequently reducing cryogenic costs. The Nb/Cu technology has been employed at CERN since the 1980s, being currently used in the LHC and...
"The Future Circular Collider (FCC), foreseen to be built at CERN, relies on the Nb/Cu technology for the 400 MHz RF system. In view of reaching the requested specifications, it is of uttermost importance to push the SRF performance of the Nb thin films to its limits. To do so, it appears critical to understand what are the underlying physical phenomena that drive the Q-slope. Such an effect...
The Nb/Cu film superconducting cavities offer several enhancements over traditional bulk niobium RF cavities, including improved mechanical and thermal stability, as well as a reduced sensitivity to DC magnetic fields. Despite these advantages, Nb/Cu film cavities produced via DC magnetron sputtering often exhibit a pronounced Q-slope issue, potentially due to the low-energy deposition...
In this study, we addressed the persistent medium-field Q-slope issue in Nb thin film cavities, which, despite their high Q at low RF fields, exhibit a significant Q-slope at medium RF fields compared to bulk Nb cavities. Traditional heat treatments, effective in reducing surface resistance and mitigating the Q-slope in bulk Nb SRF cavities, are challenging for Nb thin film cavities. We...
