Fig. 1. Procedures of surface processing

Fig. 2. Weld seam on equator of #1300S3 cavity

Fig. 3. Assembly of degaussing coil

Fig. 4. Magnetic flux expulsion experiments of two 1.3 GHz cavities

Fig. 5. Vertical test results of two 1.3 GHz cavities

Fig. 6. N-doping of 1.3 GHz cavity

Fig. 7. Comparison of vertical test results of #1300S3 and #1300S4 cavity before and after N-doping