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TY - CPAPER AU - Lagotzky, S. AU - Müller, G. AU - Navitski, A. AU - Prudnikava, A.L. AU - Tamashevich, Y. TI - Field Emission Investigation of Centrifugal-Barrel-Polished Nb Samples J2 - Proc. of International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015 AB - Actual and future SRF-accelerators require high accelerating gradient Eacc and quality factor Q0, which are often limited by enhanced field emission (EFE)* caused by surface roughness or particulates**. Various expensive surface preparation techniques (e.g. BCP, EP, HPR etc.) have been developed to obtain the required surface quality and remove the emitters. Recently, centrifugal barrel polishing (CBP) has been reconsidered to obtain a comparable surface roughness as EP with less effort***. We have started to investigate Nb samples, which were prepared as coupons in a single cell 1.3 GHz cavity by an optimized five step CBP process with a final dry ice cleaning. EFE maps showed the first emitter (1 nA) at 60 MV/m, and 32 emitters at 110 MV/m. SEM/EDX analysis of the emitting sites revealed many Al2O3 inclusions with sharp edges. Therefore, subsequent BCP (~20 μm removal) was applied to the sample. Surface analysis as well as EFE characterization of CBP treated Nb coupons with/without BCP step will be presented. PB - JACoW CY - Geneva, Switzerland SP - 237 EP - 241 KW - cavity KW - site KW - vacuum KW - survey KW - electron DA - 2015/12 PY - 2015 SN - 978-3-95450-178-6 DO - 10.18429/JACoW-SRF2015-MOPB059 UR - http://srf2015.vrws.de/papers/mopb059.pdf ER -