JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Tamura, F. AU - Hara, K. AU - Hasegawa, K. AU - Miyakoshi, R. AU - Nomura, M. AU - Ohmori, C. AU - Okita, H. AU - Seiya, K. AU - Shimada, T. AU - Sugiyama, Y. AU - Yamamoto, M. AU - Yoshii, M. ED - Cai, Yunhai ED - Nagaitsev, Sergei ED - Kim, Dong Eon ED - Marx, Michaela ED - Schaa, Volker R. W. TI - RF Systems of J-PARC Proton Synchrotrons for High-Intensity Longitudinal Beam Optimization and Handling J2 - Proc. of HB2023, Geneva, Switzerland, 09-13 October 2023 CY - Geneva, Switzerland T2 - ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams T3 - 68 LA - english AB - The application of magnetic alloy (MA) cores to the accelerating rf cavities in high intensity proton synchrotrons was pioneered for the J-PARC synchrotrons, the RCS and MR. The MA loaded cavities can generate high accelerating voltages. The wideband frequency response of the MA cavity enables the frequency sweep to follow the velocity change of protons without the tuning loop. The dual harmonic operation, where a single cavity is driven by the superposition of the fundamental and second harmonic rf voltages, is indispensable for the longitudinal bunch shaping to alleviate the space charge effects in the RCS. These advantages of the MA cavity are also disadvantages when looking at them from a different perspective. Since the wake voltage consists of several harmonics, which can cause bucket distortion or coupled-bunch instabilities, the beam loading compensation must be multiharmonic. The operation of tubes in the final stage amplifier is not trivial when accelerating very high intensity beams; the output current is high and the anode voltageis also multiharmonic. We summarize our effort against these issues in the operation of the RCS and MR for more than 10 years. PB - JACoW Publishing CP - Geneva, Switzerland SP - 305 EP - 311 KW - cavity KW - feedback KW - operation KW - controls KW - acceleration DA - 2024/04 PY - 2024 SN - 2673-5571 SN - 978-3-95450-253-0 DO - doi:10.18429/JACoW-HB2023-WEC4I1 UR - https://jacow.org/hb2023/papers/wec4i1.pdf ER -