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TY - UNPB AU - Balachandran, S. AU - Chetri, S. AU - Dhakal, P. AU - Larbalestier, D.C. AU - Lee, P.J. ED - Schaa, Volker RW ED - He, Yuan ED - Li, Lu ED - Zhao, Ning TI - Hydrogen Distribution and Hydride Precipitation in SRF Nb Revealed by Metallographic Techniques J2 - Proc. of SRF2017, Lanzhou, China, July 17-21, 2017 C1 - Lanzhou, China T2 - International Conference on RF Superconductivity T3 - 18 LA - english AB - The current issues that are of importance for SRF Nb cavities include: flux trapping depending on temperature gradient at superconducting transition, variation in flux trapping depending on precursor Nb material, and quality or process control of SRF Nb sheets that would lead to consistent performance. Our work relates to exploring microstructure correlations relevant to the above topics using coupon SRF Nb samples. Of particular importance are: a) hydride precipitation which could occur during cavity cooling below cryogenic temperatures, b) variation in surface superconducting properties and N doping, c) extent of surface damage in as received Nb sheets, and d) distribution of dislocation and substructures which lead to lattice strains in the material. The main results of our studies suggest the role of GB's in hydride formation, direct evidence of N doping preventing hydrides, and occurrence of strained lattice features depending on the surface treatment of SRF Nb. We also look at how this type of study can supplement and strengthen the effort to include quantitative microstructure based features in our understanding, and modelling of SRF superconductivity in Nb. PB - JACoW CP - Geneva, Switzerland ER -