BEAMS
In the literature: open
Frequency and temperature dependence of the anti-Q-slope
In plain words
The loss reduction with field is strong in some cavities and absent in others, and depends on the cavity frequency and temperature. A theory must explain where it appears and where it does not.
Precise statement
Measurements show the anti-Q-slope is pronounced at $f \ge 1.3\,\mathrm{GHz}$ and weak or absent at lower frequency, and depends on $T$ and on the electron mean free path set by doping. Derive the boundary in $(f,T,\text{mean free path})$ separating field-decreasing from field-increasing $R_{\mathrm{BCS}}$.
What would settle it
A predicted crossover map confirmed by cavities of several frequencies prepared with identical surface treatment.
Related problems
- Special case of Origin of the anti-Q-slope in nitrogen-doped niobium · Frequency and mean-free-path boundary is a sharper part of anti-Q-slope origin