| Buffered electropolishing (BEP) is an Nb surface treatment technique developed at Jefferson Lab. Experimental results obtained from flat Nb samples show that BEP can produce a surface finish much smoother than that produced by the conventional electropolishing (EP), while Nb removal rate can be as high as 4.67 µm/min. This new technique has been applied to the treatments of Nb SRF single cell cavity employing a vertical polishing system constructed at JLab as well as a horizontal polishing system at CEA Saclay. Preliminary results show that the accelerating gradient can reach 32 MV/m for a large grain cavity and 27 MV/m for a regular grain cavity. In this presentation, the latest progresses from the international collaboration between Peking University (PKU), CEA Saclay, and JLab on BEP will be summarized. |
