DC Field Emission Studies from Isolated Niobium Nanoparticles and Arrays

cavity performance. While good progress has been made in recent years in mitigating the negative impact of FE the physics and materials science aspects of the degradation process are not well understood. This proposal in collaboration with Dr. G. Myneni of Jefferson Labs, Newport News, Virginia, focuses on fundamental studies of FE in engineered nanoparticles and nanostructures of niobium with the intention of identifying factors and diagnostics needed to help mitigate the limitations posed by FE in SRF cavity performance. Specifically the project will undertake in Stage 1 – the construction of a versatile FE apparatus and utilize it to carry out: • DC Field Emission studies from isolated niobium nanoparticles collected on regular and large grain electropolished niobium as well as on silicon and graphite substrates. The nanoparticles will be well characterized for their structure through high resolution scanning electron microscopy (SEM) and scanning tunneling microscopy (STM). • Studies of the effect of hydrogen loading on FE from nanoparticles. Recent work at the University of Virginia has revealed that hydrogen uptake occurs in Nb nanoparticles even at room temperature and it is generally accepted that avoiding hydride formation during cavit