Comment on Field-dependent surface resistance for superconducting niobium accelerating cavities

TL;DR

This paper discusses the significance of small weak superconducting spots on niobium cavity surfaces and their impact on surface resistance, responding to prior criticism and emphasizing proximity and percolation effects.

Contribution

It highlights the role of small surface defects in superconducting niobium cavities, emphasizing their influence on surface resistance through proximity and percolation effects.

Findings

Small weak spots significantly affect surface resistance.

Proximity and percolation effects are crucial in understanding surface behavior.

Response clarifies previous criticisms about surface resistance mechanisms.

Abstract

First, this is a response to a criticism I have received about the paper which is mentioned in the title. Second, the aim is to show the important role of small (compared to coherence length) weak superconducting spots when located at the surface in connection with the proximity and percolation effects.