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TY - CONF AU - Busold, S. AU - Röcken, H. ED - Chrin, Jan ED - Schaa, Volker RW TI - Beam Intensity Modulation Capabilities for Varian's ProBeam® Isochronous Cyclotron J2 - Proc. of Cyclotrons2016, Zurich, Switzerland, September 11-16, 2016 C1 - Zurich, Switzerland T2 - International Conference on Cyclotrons and Their Applications T3 - 21 LA - english AB - Varian's ProBeam 250 MeV superconducting proton cyclotron is an isochronous cyclotron for radiological applications using pencil beam scanning mode and thus provides continuous beam (at its fundamental frequency of 72 MHz). In its clinical operation mode up to 800 nA of proton beam are specified and routinely extracted. Even more can be extracted in technical mode. The cold cathode Penning ion source provides enough protons to reach this current, and a layer-to-layer intensity modulation of the scanned beam is realized with an internal electrostatic deflector, which is used to vary the extracted beam current between maximum and zero. However, for research applications there is sometimes the request for higher flexibility, in particular for higher possible beam intensities and faster beam intensity modulation. In order to explore possibilities of the machine for such research modes, experimental investigations have been performed: Pulsed beams with repetition rates of up to 2 kHz and variable pulse lengths down to 4 μs as well as peak currents during pulse of up to 30 μA are in the accessible range with only changes at power supply level. PB - JACoW CP - Geneva, Switzerland SP - 313 EP - 315 KW - proton KW - operation KW - cyclotron KW - ion KW - ion-source DA - 2017/01 PY - 2017 SN - 978-3-95450-167-0 DO - 10.18429/JACoW-Cyclotrons2016-THP05 UR - http://jacow.org/cyclotrons2016/papers/thp05.pdf ER -