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TY - CPAPER AU - Navitski, A. AU - Elsen, E. AU - Myronenko, V. AU - Schaffran, J. AU - Tamashevich, Y. AU - Turkot, O. TI - Characterization of Surface Defects on EXFEL Series and ILC-Higrade Cavities J2 - Proc. of International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015 AB - Inspection of the inner cavity surface by an optical system is an inexpensive and useful means for surface control and identification of critical or suspicious features. Optical inspection of around 100 EXFEL series and ILC-HiGrade cavities has been performed recently using the high-resolution OBACHT system. It is a semi-automated tool based on the Kyoto camera. To gain information about the 3D topography of surface features or defects, a replica technique has been applied additionally. This is a non-destructive surface-study method reaching resolution down to 1 μm by imprinting the details of the surface onto a hardened rubber. The footprint is subsequently investigated with a microscope or profilometer. Based on these studies, several defects on the surface have been found and classified. Most of the cavity failures leading e.g. to field limitations below 20 MV/m have been identified and corresponding feedback given to the production cycle. Typical surface features and defects as well as their influence on the cavity performance will be presented and discussed. PB - JACoW CY - Geneva, Switzerland SP - 281 EP - 285 KW - cavity KW - niobium KW - SRF KW - laser KW - radiation DA - 2015/12 PY - 2015 SN - 978-3-95450-178-6 DO - 10.18429/JACoW-SRF2015-MOPB072 UR - http://srf2015.vrws.de/papers/mopb072.pdf ER -