Performance-defining properties of Nb${}_3$Sn coating in SRF cavities

Abstract

Nb${}_3$Sn has great potential to become the material of choice for fabrication of SRF cavities. The higher critical temperature of Nb${}_3$Sn potentially allows for an increased operational temperature in SRF cavities, which could enable tremendous simplification of cryogenic system, leading to significant cost reduction. We present extended characterization of a Nb${}_3$Sn coated Nb cavity prepared at Cornell University. Using combination of thermometry during cavity RF measurements, and structural and analytical characterization of the cavity cutouts, we discover Nb${}_3$Sn coating flaws responsible for the poor cavity performance. Our results clearly show degraded material quality in the cavity cutouts which exhibit significant heating during the RF testing. Results of extended comparison of cavity cutouts with different dissipation profiles not only point out the cause of significant Q-slope but also establish figures of merit for material qualities in relation to the quality of SRF performance.

References in corpus (3)

• A Review of the Properties of Nb3Sn and Their Variation with A15 Composition, Morphology and Strain State
• Superheating field of superconductors within Ginzburg-Landau theory
• Analysis of Nb3Sn surface layers for superconducting RF cavity applications

Cited by in corpus (6)

• Development of a prototype superconducting radio-frequency cavity for conduction-cooled accelerators
• Microscopic Examination of SRF-quality Nb Films through Local Nonlinear Microwave Response
• Measurements of the first-flux-penetration field in surface-treated and coated Nb: Distinguishing between surface pinning and an interface energy barrier
• Effect of layer thickness on structural, morphological and superconducting properties of Nb${}_3$Sn films fabricated by multilayer sequential sputtering
• A Time-Dependent Ginzburg-Landau Framework for Sample-Specific Simulation of Superconductors for SRF Applications
• Microscopic Investigation of rf Vortex Nucleation in Nb3Sn Films Using a Near-Field Magnetic Microwave Microscope