Undergraduate Research at Jefferson Lab

Topographical Analysis of High Performance SRF Cavity and Surface Preperation

Student: Madison DiGuilio

School: Tidewater Community College

Mentored By: Eric Lechner

During operation, Nb SRF cavities build strong electric fields to accelerate charged particles. Care must be taken to prepare surfaces that are free of geometrical defects that may facilitate low field breakdown of superconductivity. Geometrical defects on the surface of Nb and Nb₃Sn may help facilitate the formation of dissipative vortex semiloops. To conduct this research, observation of the evolution in topography post preparation was conducted to identify relevant changes to the sample surface. Locations of interest were identified on the sample surface using an optical microscope. Atomic force microscope images were analyzed for surface roughness and other topographic parameters. Local slope angle was examined to better understand magnetic field enhancement, and local suppressions were calculated to estimate the superheating field suppression factor.