TeFeN project

The aim of TeFeN experiment is to demonstrate the possibility to realize Niobium on Copper resonant cavities with performances comparable to the bulk Niobium technology and not affected by Q-slope, an issue that for over 30 years has limited the application of this technology to low accelerating field.

On Nb thick film technology for resonant cavities, nowadays, the next step is to make this process stable and reproducible, increase the performances in terms of Q and Eacc at the same levels of Nb bulk cavities, and then scale it towards cavities of standard size for the accelerators, as for example 1.3 ot 1.5 GHz elliptical cavities. For the improvement of the performances is mandatory to define a correlation between process parameters and RF performances. Moreover, recent advances in the RF performances of the Niobium on Copper cavities, have highlighted the limiting effect of trapped magnetic flux, deeply studied in bulk Niobium cavities, but until now neglected in Niobium on Copper cavities.
During the three years of TeFeN experiment, LNL and Naples Section will study various aspects of Niobium on Copper superconducting films and will try to correlate them to the RF performances of the resonant cavities and the Q-slope phenomenon, starting from the results already achieved and the new studies carried out in the other international laboratories. Specifically, the TeFeN experiment will divided in three work packages, that investigate respectively:

• WP1: development of the surface preparation of copper cavities.
• WP2: Nb thick films coated via multilayer technique.
• WP3: the effect of the residual magnetic field “trapped” in the superconducting film and its dependence on cooling.