Evidence for non-linear BCS resistance in SRF cavities

• Published in: Physica. C, Superconductivity Vol. 441; no. 1; pp. 51 - 56
• Main Authors: Bauer, P., Solyak, N., Ciovati, G.L., Eremeev, G., Gurevich, A., Lilje, L., Visentin, B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15-07-2006; Elsevier Science
• Subjects: Electrostatic, collective, and linear accelerators; Exact sciences and technology; Experimental methods and instrumentation for elementary-particle and nuclear physics; Linear collider; Niobium; Non-linear BCS resistance; Nuclear physics; Physics; RF surface resistance; Superconducting RF cavities; RF surface resistance; Linear collider; Non-linear BCS resistance; Niobium; Superconducting RF cavities; Superconducting cavity resonators; Pair breaking; BCS theory; Particle accelerators; Quality factor; Surface conductivity; Linear colliders; Non linear effect
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2006.03.056

Very powerful RF cavities are now being developed for future large-scale particle accelerators such as the International Linear Collider (ILC). The basic model for the cavity quality factor
Q-slope in high gradient SRF cavities, i.e. the reduction of
Q with increasing operating electric and magnetic fields, is the so-called thermal feedback model (TFBM). Most important for the agreement between the model and experimental data, however, is which different surface resistance contributions are included in the TFBM. This paper attempts to further clarify if the non-linear pair-breaking correction to the BCS resistance [A. Gurevich, in: Pushing the Limits of RF Superconductivity Workshop, ANL, September 2004; A. Gurevich, This conference.] is among those surface resistance contributions, through a comparison of TFBM calculations with experimental data from bulk Nb cavities built and tested at several different laboratories.