Malyshev, O.B. Dumbell, K.D. Gurevich, A.V. Gurran, L. Pattalwar, N. Pattalwar, S.M. Valizadeh, R. JACoW Geneva, Switzerland 978-3-95450-178-6 10.18429/JACoW-SRF2015-TUPB059 English 716-719 TUPB059 experiment niobium SRF superconducting-magnet data-acquisition Contribution to a conference proceedings 2015 2015-12 http://dx.doi.org/10.18429/JACoW-SRF2015-TUPB059 http://srf2015.vrws.de/papers/tupb059.pdf Superconducting RF cavities made of bulk Nb has reached a breakdown field of about 200 mT which is close to the superheating field for Nb. As it was theoretically shown* a multilayer coating can be used to enhance the breakdown field of SRF cavities. The simple example is a superconductor-insulator-superconductor (S-I-S), for example bulk niobium (S) coated with a thin film of insulator (I) followed by a thin layer of a superconductor (S) which could be a dirty niobium**. To verify such an enhancement in a presence of a DC magnetic field at 4.2 K a simple experimental facility was designed, built and tested in ASTeC. The details of experimental setup and results of the measurements will be shown at the conference.