A method based on circuit model is used to tune the first home-made 9-cell TESLA type superconducting niobium cavity at Peking University. After tuning, a flat field profile with a final π-mode frequency within 3 kHz of target frequency is achieved. The field flatness is measured by a bead-pull method, and the relative electric field is calculated from the frequency shift perturbed by the bead stepping along the axis of the cavity.
Researches on large grain superconducting cavities are carried out at SRF laboratory of Peking University. A 1.3GHz TESLA type single cell cavity and a 1.3GHz 2-cell cavity made of large grain niobium were fabricated by Peking University.With the collaboration of Jlab,the measured Eacc of the single-cell cavity reached 43.5MV/m after BCP,baking and high temperature heat treatment.
