Physical Review Accelerators and Beams
012002 (7 pp.)
A strong degradation of the unloaded quality factor with field, called high field Q slope, is commonly observed above Bp ≅ 100 mT in elliptical superconducting niobium cavities at 1.3 and 1.5 GHz. In the present experiments several 3 GHz niobium cavities were measured up to and above Bp ≅ 100 mT. The measurements show that a high field Q slope phenomenon limits the field reach at this frequency, that the high field Q slope onset field depends weakly on the frequency, and that the high field Q slope can be removed by the typical empirical solution of electropolishing followed by heating to 120°C for 48 hrs. In addition, one of the cavities reached a quench field of 174 mTand its field dependence of the quality factor was compared against global heating predicted by a thermal feedback model.
Original Publication Citation
Ciovati, G., Eremeev, G., & Hannon, F. (2018). High field Q slope and the effect of low-temperature baking at 3 Ghz. Physical Review Accelerators and Beams, 21(1), 012002. doi:10.1103/PhysRevAccelBeams.21.012002
Ciovati, G.; Eremeev, G.; and Hannon, F., "High Field Q Slope and the Effect of Low-Temperature Baking at 3 GHz" (2018). Physics Faculty Publications. 127.