Performance of a CEBAF production cavity after high-temperature heat treatment

CEBAFs production cavities are tested in a vertical configuration after appropriate chemical surface treatment prior to installation into the accelerator. The performance of these cavities is excellent often exceeding the specifications of E_acc=5 MV/m at 2 K by factors of 2 to 3. In such cases the cavities are often limited by thermal-magnetic breakdown. A cavity that exhibited a limiting gradient of E_acc⩽16.4 MV/m has been heat-treated at 1400°C for 6 hours in the presence of titanium as a solid state gettering material to improve the thermal stability of the niobium. After the heat treatment a gradient of E_acc=20.5 MV/m corresponding to a peak surface electric field of E_peak=52 MV/m has been measured. In addition to the cavity results, data on thermal conductivity and tensile properties of samples which have undergone the same treatments as the cavity are reported