Anti-Q-slope enhancement in high-frequency niobium cavities

Conference · Fri Jun 01 00:00:00 EDT 2018 · No journal information

DOI:https://doi.org/10.18429/JACoW-IPAC2018-WEPML013· OSTI ID:1484467

Martinello, Martina ^[1]; Aderhold, Sebastian ^[1]; Chandrasekaran, Saravan Kumar ^[1]; Checchin, Mattia ^[1]; Grassellino, Anna ^[1]; Melnychuk, Oleksandr ^[1]; Posen, Sam ^[1]; Romanenko, Alexander ^[1]; Sergatskov, Dmitri ^[1]

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1. Fermilab

N-doped 1.3 GHz niobium cavities showed for the first time the so-called anti-Q-slope, i.e. the increasing of the Q-factor as a function of the accelerating field. It was verified that the anti-Q-slope is consequence of the decreasing of the temperature-dependent component of the surface resistance as a function of the field. This trend is opposite compared to the increasing of the surface resistance previously observed in 1.3 GHz standard (EP, BCP, 120 C baked) niobium cavities. The effect of the different state-of-the-art surface treatments on the field dependence of the surface resistance is studied for 650 MHz, 1.3 GHz, 2.6 GHz and 3.9 Ghz cavities. This proceeding shows that the field dependence of the temperature-dependent component of the surface resistance has a strong frequency dependence and that the anti-Q-slope may appear even in clean niobium cavities if the resonant frequency is high enough, suggesting new routes toward the understanding of the anti-Q-slope effect.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: 89243024CSC000002; AC02-07CH11359
• OSTI ID: 1484467
• Report Number(s): FERMILAB-CONF-18-611-TD; oai:inspirehep.net:1697800
• Resource Type: Conference paper
• Conference Information: Journal Name: No journal information
• Country of Publication: United States
• Language: English

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