JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Sun, Z. AU - Arias, T. AU - Baraissov, Z. AU - Dukes, C. AU - Johnson-McDaniel, D. AU - Liepe, M. AU - Muller, D.A. AU - Oseroff, T.E. AU - Porter, R.D. AU - Salim, M. AU - Sitaraman, N. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Lesage, Ana ED - Schaa, Volker R.W. TI - Surface Oxides on Nb and Nb₃Sn Surfaces: Toward a Deeper Understanding J2 - Proc. of SRF2021, East Lansing, MI, USA, 28 June-02 July 2021 CY - East Lansing, MI, USA T2 - International Conference on RF Superconductivity T3 - 20 LA - english AB - Surface oxides on Nb and Nb₃Sn SRF cavities, as a thin ’dirty’ layer, could be critical to their performance as suggested by recent theory. Although these oxides have been studied in the past, we intend here to provide a deeper understanding based on a systematic study on coupon samples that have been processed under the different conditions currently used in SRF cavity treatments. Our aim is to obtain a more complete picture of the oxide evolution. This then might help to explain the observed cavity performance variation, and might allow designing a process to achieve a designed, optimized surface with controlled oxides types and thickness. We find that the surface oxides are in amorphous phase that exhibits normal conducting behaviors, while the pentoxide further degrades with time. Also, we observed a thin hydroxide layer on the outermost surface and possibly Nb(OH)x motifs in the bulk. Moreover, distinctive oxide structures were found in Nb₃Sn samples from vapor diffusion, electroplating, and sputtering. The semiconducting SnOx appeared through the oxide depth in vapor diffused Nb₃Sn, while a ~1 nm SnOx layer merely exists at the outermost surface of electroplated Nb₃Sn. PB - JACoW Publishing CP - Geneva, Switzerland SP - 836 EP - 840 KW - SRF KW - niobium KW - cavity KW - superconductivity KW - electron DA - 2022/10 PY - 2022 SN - 2673-5504 SN - 978-3-95450-233-2 DO - doi:10.18429/JACoW-SRF2021-THPTEV004 UR - https://jacow.org/srf2021/papers/thptev004.pdf ER -