An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about one order of magnitude better than with earlier methods and surface resistance resolution of ~ 1 micro-Ohm at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.
@article{arxiv.1201.5386,
title = {Low temperature laser scanning microscopy of a superconducting radio-frequency cavity},
author = {G. Ciovati and Steven M. Anlage and C. Baldwin and G. Cheng and R. Flood and K. Jordan and P. Kneisel and M. Morrone and G. Nemes and L. Turlington and H. Wang and K. Wilson and S. Zhang},
journal= {arXiv preprint arXiv:1201.5386},
year = {2012}
}
Comments
19 pages, 17 figures, submitted to Rev. Sci. Instrum