Accelerator Seminar: Zeming Sun - Functionalizing Advanced Materials and Surfaces in Superconducting RF

Title: Functionalizing Advanced Materials and Surfaces in Superconducting RF 


Materials scientists seek to contribute to the development of next-generation SRF accelerating cavities. In this seminar, I present recent achievements and learnings in designing advanced SRF materials and surfaces, including Nb3Sn [1,2], ZrNb(CO) [3,4], and Au/Nb surface design [5,6]. Efforts involve electrochemical synthesis, phase transformation, and surface chemistry, which are closely coupled with superconducting properties, SRF performance, and engineering considerations. I develop electrochemical processes for Sn, Zr, and Au on the Nb surface, an essential step in my investigation for producing high-quality Nb3Sn, ZrNb(CO), and Au/Nb structures. I design a custom chemical vapor deposition system to offer additional growth options. I reveal fundamental mechanisms in vacuum baking (oxygen processing) and nitrogen processing, linked to collective contributions from second phase formation and surface oxides [6]. I identify low-dielectric-loss ZrO2 on Nb and NbZr(CO) surfaces. These advancements provide materials science approaches dealing with fundamental and technical challenges to build high-performance, multi-scale, robust SRF cavities for particle accelerators and quantum applications.