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- A. Cianchi, L. Catani, A. Cianchi, S. Tazzari
INFN-Roma II, Roma
- Y.H. Akhmadeev
Institute of High Current Electronics, Tomsk
- A. Andreone, G. Cifariello, E. Di Gennaro, G. Lamura
Naples University Federico II, Napoli
- J.L. Langner
The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
- R.R. Russo
Università di Roma II Tor Vergata, Roma
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Thin niobium film coated copper RF cavities are an interesting possible alternative to bulk-Nb cavities since copper is much cheaper than niobium, it has higher thermal conductivity and a better mechanical stability. Unfortunately, the observed degradation of the quality factor with increased cavity voltage of sputtered accelerating cavities restricts their usage in future large linear accelerators needing gradients higher than 15MV/m. We are developing an alternate deposition technology, based on a cathodic arc system working in UHV conditions. Its main advantages compared to standard sputtering are the ionized state of the evaporated material, the absence of gases to sustain the discharge, the much higher energy of atoms reaching the substrate surface and the possibility of higher deposition rates. To ignite the arc we use a Nd-YAG pulsed laser focused on the cathode surface that provides a reliable and ultraclean trigger. Recent results on the characterization of niobium film samples produced under different conditions are presented showing that the technique can produce bulk-like films suitable for RF superconducting applications.
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