Fabrication and Evaluation of Superconducting Single-Cell Cavities Manufactured Using Various Materials and Methods

Six cavities of the same type (TESLA-like shape) made from six different niobium sources or types were produced at KEK using various materials and fabrication methods. Throughout these sequential in-house fabrications, comparisons of the properties of the various materials for use in superconducting radio-frequency cavities were conducted. The advantages and disadvantages of these properties, together with different fabrication methods, were examined. The cavities were fabricated primarily using existing facilities within KEK to control the fabrication quality. Vertical tests to evaluate single-cell cavity performances were conducted at the Superconducting RF Test Facility in KEK. The technical details of each fabrication method and the obtained high-gradient test results are described and discussed.