Dziuba, F.D. Aulenbacher, K. Barth, W.A. Basten, M. Busch, M. Gettmann, V. Heilmann, M. Kürzeder, T. Miski-Oglu, M. Podlech, H. Salvatore, J. Schnase, A. Schwarz, M. Yaramyshev, S. JACoW Publishing Geneva, Switzerland 2226-0366 978-3-95450-194-6 10.18429/JACoW-LINAC2018-THPO073 English 859-862 THPO073 cavity linac heavy-ion SRF MMI Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-LINAC2018-THPO073 http://jacow.org/linac2018/papers/thpo073.pdf Future research programs at GSI in the field super heavy element (SHE) synthesis require high intense heavy ion beams above the coulomb barrier and high average particle currents. The upcoming demands exceed the technical opportunities of the existing UNIversal Linear ACcelerator (UNILAC). Consequently, a new dedicated superconducting (sc) continuous wave (cw) linac is crucial to keep the SHE research program at GSI competitive on a high level. Recently the first linac section, serving as a prototype to demonstrate the reliable operability of 217 MHz multi gap crossbar-H-mode (CH) cavities under a realistic accelerator environment, has been extensively tested with a heavy ion beam delivered from the GSI High Charge State Injector (HLI). Fulfilling its role as a key component of the whole demonstrator setup. The first sc 217 MHz CH cavity (CH⁰) successfully accelerated heavy ions up to the design beam energy and even beyond at high beam intensities and full transmission. In this contribution the rf commissioning and the first beam operation of the cavity is presented.