Author: Sung, Z-H.
Paper Title Page
Direct Correlation of State of the Art Cavity Performance With Surface Nb Nano-Hydrides Cutouts Observed via Cryogenic AFM  
  • Z-H. Sung
    Fermilab, Batavia, Illinois, USA
  There was no abstract provided by the author.  
slides icon Slides TUFUB1 [8.368 MB]  
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TUP061 Gradients of 50 MV/m in TESLA Shaped Cavities via Modified Low Temperature Bake 586
  • D. Bafia, J. Zasadzinski
    IIT, Chicago, Illinois, USA
  • D. Bafia, A. Grassellino, O.S. Melnychuk, A.S. Romanenko, Z-H. Sung
    Fermilab, Batavia, Illinois, USA
  This paper will discuss the 75/120 C modified low temperature bake capable of giving unprecedented accel-erating gradients of above 50 MV/m for 1.3 GHz TESLA-shaped niobium SRF cavities in CW operation. A bifurca-tion in the Q0 vs Eacc curve is observed after retesting cavities without disassembly in between, yielding per-formance that ranges from exceptional to above state-of-the-art. Atomic Force Microscopy studies on cavity cut-outs gives a possible mechanism responsible for this branching in performance, namely, the dissociation and growth of room temperature niobium nano-hydrides that exist near the RF surface, which are made superconduct-ing only through the proximity effect. In-situ low temper-ature baking of cavity cutouts reveals a dissociation of these room temperature nano-hydrides, which could ex-plain the higher performance of cavities subject to similar in-situ heating in the dewar.  
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About • paper received ※ 23 June 2019       paper accepted ※ 03 July 2019       issue date ※ 14 August 2019  
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