Beam Measurements in the MedAustron Synchrotron With Slow Extraction and Off-Momentum Operation

The MedAustron Ion Therapy Center is a medical accelerator facility for hadron therapy cancer treatment using protons and carbon ions. The facility features 4 irradiation rooms, three of which are dedicated to clinical operation and a fourth one dedicated to non-clinical research. The latter was handed over to researchers in autumn 2016. A 7 MeV/n injector feeds a 77 m circumference synchrotron which provides beams for treatment and research. Routine verification measurements in the synchrotron involve beam emittance, dispersion as well as tunes and chromaticity. The horizontal and vertical emittance are measured using scraping plates and a direct current transformer. The dispersion function in the ring is determined by sweeping the synchrotron RF frequency while measuring the beam position in the shoe-box pick-ups. The horizontal and vertical betatron tune and chromaticity are measured with Direct Diode Detection electronics, developed at CERN, while changing the beam position with the RF radial loop. The beam is kept off-momentum, thus in dispersive regions the closed orbit is largely offset from the central orbit. Methods for beam measurements in the synchrotron are presented.