ATS Seminar - High Performance Nb SRF Cavities for Accelerators and Quantum Science

by Daniel Bafia

Tuesday 16 Jun 2026, 11:00 → 12:00 Europe/Zurich

503/1-001 - Council Chamber (CERN)

Speaker:

• Daniel Bafia, Associate Scientist
• Superconducting Quantum Materials and Systems Division
• Fermilab

Abstract:

This presentation will highlight recent R&D efforts at Fermilab focused on niobium superconducting radio-frequency cavities for high Q and high gradient accelerator applications, with extensions to quantum information science. New insights into RF dissipation are obtained through surface processing approaches including nitrogen incorporation, controlled oxygen diffusion, and optimized electropolishing, which enable systematic reduction of surface resistance while preserving strong high-field performance. These results are enabled by combining precision cryogenic RF measurements with advanced materials characterization. The same processing approaches demonstrate adaptability across cavity frequencies and geometries, including recent studies on non-elliptical structures such as the barrel cell cavity developed at CERN, underscoring their relevance to evolving accelerator concepts and ongoing collaborative efforts. In alignment with these efforts, Fermilab is contributing to the FCC 800 MHz SRF program, where high-Q processing strategies are being explored in collaboration with CERN across both single-cell and multicell cavity development. This work builds on high-Q recipes first developed at Fermilab and supports their extension toward large-scale accelerator applications. In parallel, variants of these resonant structures not only enable ultra-low-loss, long-coherence quantum systems, but also serve as highly sensitive testbeds for materials characterization. By reducing complex multilayer devices to controlled single-interface geometries, key loss channels associated with amorphous niobium oxide, niobium hydrides, and dielectric substrates can be directly identified and quantified. Together, these results establish a materials-driven framework for controlling dissipation in superconducting resonators. Beyond accelerators, this level of control enhances sensitivity in dark sector searches, highlighting the broader impact of SRF technology across multiple frontiers of physics.

Bio:

Dr. Daniel Bafia is an Associate Scientist at the Superconducting Quantum Materials and Systems (SQMS) Center at Fermilab, where his research sits at the intersection of accelerator technology and quantum information science. He received his PhD from the Illinois Institute of Technology in 2020, and his work focuses on superconducting materials and ultra-low-loss resonators for accelerator and quantum computing applications, with particular emphasis on dielectric loss, superconducting dissipation, and vortex-induced microwave losses at millikelvin temperatures.

 ATS Seminar Organisers
A. Dallocchio (EN), E. Metral (BE),  T. Stora (SY), A. Sublet (TE)

 

Bafia-CERN-Seminar_vF.pdf