Speaker
Alexander Romanenko
(FNAL)
Description
Recent Fermilab discoveries of nitrogen doping and effective magnetic flux expulsion allow quality factors in bulk niobium SRF cavities several times higher than the previous state-of-the-art from only two years ago. The combined approach using both of these techniques allows to minimize both residual and BCS surface resistances leading to the world-record quality factors of >2e11 corresponding to surface resistance of <1.5 nOhm up to the highest fields of 20+MV/m. Possibility of such high quality factors holds the potential to dramatically decrease a dynamic heat load and affect the choice of the optimal operating temperature of FCC.
In this contribution I will briefly review these recent developments and outline their potential impact on the design of FCC.
The plans for Fermilab Nb3Sn SRF cavity work for future 4.2K industrial (and potential FCC) applications will be discussed as well.
