Xie, Y. Kanareykin, A. Khabiboulline, T.N. Lunin, A. Poloubotko, V. Rathke, J. Rowe, A.M. Solyak, N. Yakovlev, V.P. JACoW Geneva, Switzerland 978-3-95450-178-6 10.18429/JACoW-SRF2015-THPB105 English 1397-1399 THPB105 cavity coupling niobium SRF HOM Contribution to a conference proceedings 2015 2015-12 http://dx.doi.org/10.18429/JACoW-SRF2015-THPB105 http://srf2015.vrws.de/papers/thpb105.pdf Superconducting ILC-type cavities have an rf input coupler that is welded on. A detachable input coupler will reduce conditioning time (can be conditioned separately), reduce cost and improve reliability. The problem with placing an extra flange in the superconducting cavity is about creating a possible quench spot at the seal place. Euclid Techlabs LLC has developed a coaxial coupler which has an on the surface with zero magnetic field (hence zero surface current). By placing a flange in that area we are able to avoid disturbing surface currents that typically lead to a quench. The coupler is optimized to preserve the axial symmetry of the cavity and rf field. The surface treatments and rf test of the proto- type coupler with a 1.3 GHz ILC-type single-cell cavity at Fermilab will be reported and discussed.