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 - Thune, Z.L. AU - Bieler, T.R. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Schaa, Volker R.W. ED - Thomas, Paul W. TI - The Influence of Sample Preparation, Soak Time, and Heating Rate on Measured Recrystallization of Deformed Polycrystalline Niobium 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 - Improving accelerator performance relies on consistent production of high-purity niobium superconducting radiofrequency (SRF) cavities. Current production uses an 800 °C 3 hr heat treatment, but 900-1000 °C can improve cavity performance via recrystallization (Rx) and grain growth. As Rx is thermally activated, increasing the temperature and/or the heating rate could facilitate a reduction in geometrically necessary dislocation (GND) density that is associated with the degradation of cavity performance via trapped magnetic flux. Recent work shows that increasing the annealing temperature increased the Rx fraction in cold-rolled polycrystalline niobium. However, the influence of heating rate on the extent of Rx was minimal with a 3 hr soak time. To further assess the influence of heating rate on measured Rx, as well as the effects of sample preparation, electron backscatter diffraction (EBSD) was used to quantify the extent of Rx on samples annealed at a single temperature with different soak times. Comparing samples with different surface preparation shows that pinned grain boundaries on the free surface reveal a much smaller grain size than below the surface. PB - JACoW Publishing CP - Geneva, Switzerland SP - 863 EP - 867 KW - cavity KW - ECR KW - niobium KW - SRF KW - electron DA - 2023/09 PY - 2023 SN - 2673-5504 SN - 978-3-95450-234-9 DO - doi:10.18429/JACoW-SRF2023-WEPWB116 UR - https://jacow.org/srf2023/papers/wepwb116.pdf ER -