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 - Maniscalco, J.T. AU - Aderhold, S. AU - Arkan, T.T. AU - Bafia, D. AU - Bevins, M.E. AU - Checchin, M. AU - Gonnella, D. AU - Grabowski, A.J. AU - Hogan, J. AU - Kaluzny, J.A. AU - Porter, R.D. AU - Posen, S. AU - Reece, C.E. AU - Savransky, D. AU - Vennekate, H. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - Flux Expulsion Testing for LCLS-II-HE Cavity Production 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 - Nitrogen-doped niobium SRF cavities are sensitive to trapped magnetic flux, which decreases the cavity intrinsic Q₀. Prior experimental results have shown that heat treatments to 900°C and higher can result in stronger flux expulsion during cooldown; the precise temperature required tends to vary by vendor lot/ingot of the niobium material used in the cavity cells. For LCLS-II-HE, to ensure sufficient flux expulsion in all cavities, we built and tested single-cell cavities to determine this required temperature for each vendor lot of niobium material to be used in cavity cells. In this report, we present the results of the single-cell flux expulsion testing and the Q₀ of the nine-cell cavities built using the characterized vendor lots. We discuss mixing material from different vendor lots, examine the lessons learned, and finally present an outlook on possible refinements to the single-cell technique. PB - JACoW Publishing CP - Geneva, Switzerland SP - 876 EP - 879 KW - cavity KW - cryomodule KW - niobium KW - SRF KW - ECR DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-WEPWB120 UR - https://jacow.org/srf2023/papers/wepwb120.pdf ER -