JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
@inproceedings{balachandran:srf2023-mopmb041, author = {S. Balachandran and T.R. Bieler and S. Chetri and P. Dhakal and P.J. Lee and Z.L. Thune and A-M. Valente-Feliciano}, % author = {S. Balachandran and T.R. Bieler and S. Chetri and P. Dhakal and P.J. Lee and Z.L. Thune and others}, % author = {S. Balachandran and others}, title = {{Microstructure Development in a Cold Worked SRF Niobium Sheet After Heat Treatments}}, % booktitle = {Proc. SRF'23}, booktitle = {Proc. 21th Int. Conf. RF Supercond. (SRF'23)}, pages = {191--196}, eid = {MOPMB041}, language = {english}, keywords = {cavity, ECR, SRF, niobium, radio-frequency}, venue = {Grand Rapids, MI, USA}, series = {International Conference on RF Superconductivity}, number = {21}, publisher = {JACoW Publishing, Geneva, Switzerland}, month = {09}, year = {2023}, issn = {2673-5504}, isbn = {978-3-95450-234-9}, doi = {10.18429/JACoW-SRF2023-MOPMB041}, url = {https://jacow.org/srf2023/papers/mopmb041.pdf}, abstract = {{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.}}, }