Chouhan, V. Ring, T.J. Viklund, E.A.S. Wu, G. JACoW Publishing Geneva, Switzerland 2673-5504 978-3-95450-234-9 10.18429/JACoW-SRF2023-WEIXA05 English 641-645 cavity niobium SRF cathode radio-frequency Contribution to a conference proceedings 2023 2023-09 https://doi.org/10.18429/JACoW-SRF2023-WEIXA05 https://jacow.org/srf2023/papers/weixa05.pdf The nitrogen doping (N-doping) process is applied to niobium (Nb) superconducting cavities to enhance their quality factors. The N-doping is followed by an electropolishing process that provides the final surface of the cavities. A controlled EP process is necessary to get the benefit of N-doping and achieve a high accelerating gradient. We have performed electropolishing of N-doped Nb surface under various conditions to understand their impact on the surface. A modified EP process was developed to obtain a smooth pit-free surface.