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 - Balachandran, S. AU - Bieler, T.R. AU - Chetri, S. AU - Dhakal, P. AU - Lee, P.J. AU - Thune, Z.L. AU - Valente-Feliciano, A-M. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Microstructure Development in a Cold Worked SRF Niobium Sheet After Heat Treatments J2 - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023 CY - Grand Rapids, MI, USA T2 - International Conference on RF Superconductivity T3 - 21 LA - english AB - Bulk Nb for TESLA shaped SRF cavities is a mature technology. Significant advances are in order to push Q₀’s to 10¹0⁻¹¹(T= 2K), and involve modifications to the sub-surface Nb layers by impurity doping. In order to achieve the lowest surface resistance any trapped flux needs to be expelled for cavities to reach high Q₀’s. There is clear evidence that cavities fabricated from polycrystalline sheets meeting current specifications require higher temperatures beyond 800 °C leads to better flux expulsion, and hence improves Q₀. Recently, cavities fabricated with a non-traditional Nb sheet with initial cold work due to cold rolling expelled flux better after 800 °C/3h heat treatment than cavities fabricated using fine-grain poly-crystalline Nb sheets. Here, we analyze the microstructure development in Nb from the vendor supplied cold work non- annealed sheet that was fabricated into an SRF cavity as a function of heat treatment building upon the methodology development to analyze microstructure being developed by the FSU-MSU-UT, Austin-JLAB collaboration. The results indicate correlation between full recrystallization and better flux expulsion. PB - JACoW Publishing CP - Geneva, Switzerland SP - 191 EP - 196 KW - cavity KW - ECR KW - SRF KW - niobium KW - radio-frequency DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-MOPMB041 UR - https://jacow.org/srf2023/papers/mopmb041.pdf ER -