Speaker
Description
Since its discovery at the beginning of the twentieth century, Superconductors have drown their paths into various fields from electromagnets with unprecedented magnetic fields to state of the art electronic circuits and radiofrequency cavities for particle accelerators. Despite the fact that they have enabled a real breakthrough in particular in the field of SRF cavities, Superconductors still witness performance limitations when exposed to intense magnetic fields.
We are exploring an original approach to improve the performance of bulk Niobium RF cavities through surface engineering with ALD superconducting multilayer capable of screening efficiently the magnetic fields and therefore inhibiting vortices penetration in Niobium SRF cavities [1]. This multilayer consists in a stack of superconducting films a few hundred nanometer thick separated by a 5 to 10 nm insulating layer. To our knowledge, Atomic layer deposition (ALD) is the only deposition technique able of providing high structural and chemical homogeneity over large surfaces with complex shapes.
To that end, we studied an ALD-deposited multilayer based on AlN and NbTiN superconducting films with critical temperature up to 16 K. Chemical and structural analysis will be presented as well as superconducting measurements such as critical temperatures and SQUID. We will also give updates on the development of our ALD-system dedicated to cavity coatings and we will share some of our preliminary results.
[1] A.Gurevich,”Enhancement of RF breakdown field of SC by multilayer coating”.Appl. Phys.Lett, 2006.
