Kanazawa, M. Hirao, Y. Itano, A.I. Morii, Y. Noda, K. Sato, K. Shigeta, M. Sudou, M. Takada, E. Toyoda, E. Tsuzuki, N. Yagi, T. Yamagishi, T. Yamazaki, C. JACoW Publishing Geneva, Switzerland 2226-0358 978-3-95450-254-7 10.18429/JACoW-ICALEPCS1991-S12FC07 English 434-437 controls synchrotron acceleration feedback electron Contribution to a conference proceedings 1992 1992-12 https://doi.org/10.18429/JACoW-ICALEPCS1991-S12FC07 https://jacow.org/icalepcs1991/papers/s12fc07.pdf HIMAC is a heavy Ion accelerator facility dedicated to the medical use, especially for the clinical treatment of tumors. The ion species required for the clinical treatment range from ⁴He to ⁴⁰Ar. An RF control system of the HIMAC synchrotron has been constructed. In this control system we have adopted a digital feed back system with a digital synthesizer (DS). Combining a high power system, performance of the control system have been tested in a factory (Toshiba) with a simulator circuit of the synchrotron oscillation. Following this test, we had beam acceleration test with this control system at TARN-II in INS (Institute for Nuclear Study, University of Tokyo). This paper describes the RF control system and its tested results.