Busold, S. Partowidjojo, A.S. Röcken, H. Schippers, J.M. JACoW Geneva, Switzerland 978-3-95450-167-0 10.18429/JACoW-Cyclotrons2016-THP06 English 316-318 THP06 cathode ion ion-source cyclotron operation Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-Cyclotrons2016-THP06 http://jacow.org/cyclotrons2016/papers/thp06.pdf The cold cathode Penning ionization gauge (PIG) type proton source of the VARIANÂ’s ProBeam® 250 MeV superconducting isochronous cyclotron suffers from the usual cathode/chimney erosion during operation. Furthermore, a relatively high hydrogen gas flow is needed to generate a proton beam in the μA range, which induces conditions for RF operation below optimum. In the quest to increase cathode/chimney life time and thereby directly extend service intervals, thus reducing the total cost of ownership, several experimental investigations have been performed at a dedicated test bench at PSI, Switzerland, including material studies, a detailed operation analysis and switching to a hot cathode design.