Field Shielding of N\u3csub\u3eB\u3c/sub\u3eT��N Based Multilayer Structure for Accelerating Cavities

Over the past few decades, bulk niobium (Nb) has been the material of choice for superconducting radio frequency (SRF) cavities used in particle accelerators to achieve higher accelerating gradients and lower RF losses. Multi-layer (SIS) structures consisting of alternating thin layers of superconductor(S) and insulator(I) deposited on a bulk Nb have been proposed to enhance the peak surface magnetic field and sustain a higher accelerating gradient. In this study, multilayers based NbTiN and AlN deposited on bulk Nb are used to test the proposed enhancement using the DC magnetic Hall probe technique. The technique detects a penetrating magnetic field through the multilayer sample as it is placed under an external mag-netic field produced by a magnetic coil. This work reports the characterization and measurements of the magnetic field of full flux penetration through single layers of NbTiN and bilayers of NbTiN/AlN on bulk Nb