Proceedings of the 31st International Linear Accelerator Conference
31st International Linear Accelerator Conference (LINAC2022), August 28-September 2, 2022, Liverpool, United Kingdom
Currently, fine grain niobium (Nb) (grain size ∼ 50 µm) and large grain Nb (grain size of a few cm) are being used for the fabrication of superconducting radio frequency (SRF) cavities. Medium grain forged ingot with grain size of a few hundred µm may be beneficial for cost-effectiveness as well as providing better performance for future SRF-based accelerators. Forged ingot Nb with medium grain size is a novel production method to obtain Nb discs used for the fabrication of superconducting radio frequency cavities. We have fabricated two 1.5 GHz single cell cavities made from forged Nb ingot with a residual resistivity ratio of ∼ 100. The cavities were chemically and mechanically polished and heat-treated in the temperature range of 650-1000 C before the rf test. One of the cavities reached an accelerating gradient of ∼34 MV/m with a quality factor Q > 1e10, while the second cavity was limited at 14 MV/m, likely due to a weld defect at the equator.
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Original Publication Citation
Dhakal, P., Khanal, B. D., Ciovati, G., & Myneni, G. R. (2022) Evaluation of single-cell cavities made of forged ingot niobium at Jefferson Lab. In P. McIntosh, G. Burt, R. Apsimon, and V.R.W. Schaa (Eds.), Proceedings of the 31st International Linear Accelerator Conference. (pp. 828-831) Joint Accelerator Conferences Website. http://dx.doi.org/10.18429/JACoW-LINAC2022-THPOGE16
Dhakal, P.; Khanal, Bashu D.; Ciovati, Gianluigi; and Myneni, G. R., "Evaluation of Single-Cell Cavities Made of Forged Ingot Niobium at Jefferson Lab" (2022). Physics Faculty Publications. 703.