  In this study we will show a new method of polishing for Nb3Sn cavities known
as centrifugal barrel polishing (CBP). Using this method, Nb3Sn coated samples
are polished to a surface roughness comparable to a traditional Nb cavity after
electropolishing (EP). We also investigate different methods of cleaning the
Nb3Sn surface after CBP to remove residual abrasive particles. The polished
Nb3Sn surface is analyzed using confocal laser microscopy, and scanning
electron microscopy (SEM) is used to image the surface and measure the surface
roughness after polishing. Transmission electron microscopy (TEM) is also used
for high resolution analysis of the surface after polishing. Finally, we show
that centrifugal barrel polishing can improve the performance of a Nb3Sn SRF
cavity.
