SIMS Investigation of Furnace-Baked Nb

Abstract

Impurity-alloying SRF cavities via thermal diffusion has yielded highly efficient Nb resonators. Recently, SRF cavities vacuum heat treated at 300 – 400 ° C for a few hours have exhibited high quality factors and behavior typical of alloyed cavities. Using secondary ion mass spectrometry, we investigated the interstitial concentration of carbon, nitrogen, and oxygen in niobium prepared by this method. Our investigation shows that oxygen is likely the primary diffusant in such recipes and is well-described by Ciovati’s model for native niobium oxide dissolution and oxygen diffusion.