铌三锡镀膜射频超导腔的研究进展

Over the past decades, the field of superconducting radio frequency (SRF) technology has witnessed remarkable advancements, with SRF cavities constructed from high-purity niobium (Nb) materials becoming prevalent in particle accelerator applications. However, due to the inherent physical and chemical limitations of the material, the performance of Nb cavities has stagnated, falling short of the requirements for the next generation of superconducting accelerators. In contrast, Nb?Sn exhibits superior characteristics, including higher superconducting transition temperatures, stronger magnetic field thresholds for overheating, and lower surface resistance atResearch progress of Nb3Sn-coated radio frequency superconducting cavity equivalent temperatures. Moreover, the implementation of Nb?Sn-coated cavities enables an increase in operating temperature from 2 K to 4.2 K, significantly reducing the operational costs of the system. This paper initially introduces the fundamental concepts of SRF cavities and subsequently highlights the recent advancements in the preparation of Nb?Sn-coated superconducting cavities through deposition methods. Notably, the highest performance benchmark for Nb?Sn-coated cavities has been achieved by Fermilab, utilizing the vapor diffusion method in a 1.3 GHz ellipsoidal single-cell cavity: at 4.4 K, the acceleration gradient attained was approximately 22.5 MV/m, with a quality factor reaching approximately 2×101? at 10 MV/m. Theoretically, the acceleration gradient of Nb?Sn-coated cavities can potentially reach up to approximately 90 MV/m, suggesting considerable room for further performance enhancement.