Today's update focuses on Dr. Francis Lockwood Estrin.
Dr. Francis Lockwood Estrin is a Post-Doctoral Research Assistant working as part of the University of Liverpool and part ASTeC in Daresbury Laboratory. His role is to research the A-Symmetrical HiPIMS and its application for superconducting thin films, this is split between work In Daresbury producing thin films and work at Liverpool investigating the plasma conditions. Prior to this Francis worked at QinetiQ on Ion Thrusters a space propulsion technology. During this period, he worked on the BepiColombo mission mercury among other projects.Bulk niobium has been the material of choice for superconducting RF-accelerators as it is the highest critical temperature (Tc = 9.25 K) and highest lower critical field (Hc1 = 0.18 T) of the pure metal superconductors. However, manufacturing cavities from bulk requires a compromise between desirable superconducting qualities (Tc and Hc) and material properties (thermal conductivity and structural stability). It is possible to separate these requirements by instead constructing cavities as thin superconducting films deposited on desirable bulk substrates. This can lead to improved Q-factors when using niobium as a superconductor, but also allows the use of niobium alternative such as MgB2, NbTiN, V3Si, Nb3Sn, etc. which could not be machine for bulk. These niobium alternatives can have significantly higher Tc and second critical fields Hc2 than niobium, for examples V3Si with Tc =17 K, Hc2= 24.5 T and NbN Tc= 16.2 K, Hc2 = 15 T, far higher than niobium. Given the superconducting properties these alternatives there is the potential for superconducting RF cavities with higher accelerating fields and Q-factor.
This talk will outline the process and technologies currently used for the production of high-quality thin films in RF-Accelerator cavities, with specific focus on physical vapour deposition (PVD) by magnetron sputtering. It will explain how these processes work, how thin films are tested. The talk will also report on the progress made by the Vacuum Science Group, of ASTeC based at Daresbury Laboratory in the manufacture of thin films superconducting thin films, including niobium thin film and niobium alternatives such as V3Si, mgB2 and NbNTi as well as multi-layered composite films.
Sign up for the annual event online