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TY - CONF AU - Konomi, T. AU - Kako, E. AU - Michizono, S. AU - Nagata, T. AU - Nojima, T. AU - Sakai, H. AU - Umemori, K. ED - Schaa, Volker RW ED - Pei, Guoxi ED - Chin, Yong Ho ED - Fu, Shinian ED - Zhao, Ning TI - Niobium Sample Analysis for Nitrogen Infusion and Doping J2 - Proc. of LINAC2018, Beijing, China, 16-21 September 2018 CY - Beijing, China T2 - Linear Accelerator Conference T3 - 29 LA - english AB - KEK has been investigating the better conditions of the heat treatment in nitrogen, which are called as nitrogen doping and nitrogen infusion. We have tried to understand the high gradient performance of the cavity from the analyses of samples which were prepared in the same conditions for the cavity. The main tools are D-SIMS for the depth profile of the elemental concentration, XPS for composition analysis and SQUID magnetometry for the critical DC magnetic field measurement. The difference in the depth profiles of the nitrogen, carbon and oxygen between the heat treatment conditions was observed in vacuum and furnace temperature of nitrogen infusion by D-SIMS and XPS. Such a difference correlates with the vortex penetration field measured by SQUID. In particular, that of nitrogen doping sample was greatly degraded, while that of nitrogen infusion sample was slightly improved. The tendency is similar to the RF high gradient test results. Details of the sample analysis are shown in this presentation. PB - JACoW Publishing CP - Geneva, Switzerland SP - 506 EP - 509 KW - cavity KW - niobium KW - vacuum KW - injection KW - ECR DA - 2019/01 PY - 2019 SN - 2226-0366 SN - 978-3-95450-194-6 DO - DOI: 10.18429/JACoW-LINAC2018-TUPO073 UR - http://jacow.org/linac2018/papers/tupo073.pdf ER -