At high field levels, field emission losses in superconducting cavities have an adverse effect in both reducing the otherwise extremely high Q > 10^9, and the magnetic breakdown field bringing it well below the critical magnetic field of the superconductor. The two effects may well be related as field enhancing whiskers responsible for the field emission losses can be driven normal thus reducing the magnetic breakdown field. Both the beneficial and deleterious effects of anodizing the inner surface of superconducting cavities are discussed and analyzed.

6 pages