Tuning methods for HIMAC multiple-energy operation

Beam stability of the multiple-energy operation at HIMAC synchrotron was improved for the fast raster-scanning irradiation. In order to improve the transverse stability, the working point of the betatron tune was investigated during the acceleration section. The signals were collected from the beam position monitor using a fast data-acquisition unit. The temporal evolution of the horizontal and vertical betatron tune was evaluated by using the short time Fourier transforms. Analyzed results showed that the working point of the betatron tune in the acceleration section passed thorough the 3rd - and 4th -order coupling resonance line. In order to keep the working point within the desirable operating region, the current patterns of the power supplies for the quadrupole magnets were corrected by using the variation of the betatron tune. The experimental results showed that the working point could be successfully stabilized, and the undesirable beam losses could be reduced during the acceleration section.The second International Particle Accelerator Conference (IPAC´11