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Tamura, Fumihiko
no journal, ,
Low level rf (LLRF) control systems are important for stable beam acceleration in proton synchrotrons. We developed LLRF control systems for J-PARC synchrotrons (RCS and MR) using digital circuits to realize precise and reproducible rf control. The systems are in operation since 2007. In the presentation, the overview and details of the J-PARC LLRF control system, also, the beam commissioning results using the LLRF control system, are presented. For acceleration of high intensity beams, beam loading compensation is indispensable. We employ the rf feedforward method and developed the multiharmonic feedforward modules for J-PARC synchrotrons. The impedances seen by the beam have been successfully reduced by the feedforward system. The commissioning methodology and commissioning results are presented.
Watanabe, Yasuhiro
no journal, ,
Recent high-intensity proton synchrotron has many quadrupole magnet families for the purpose of flexible beam operation. In J-PARC RCS, main magnet system consists of one bending and seven quadrupole families. Their magnet families are excited using a resonant circuit and the current waveform is a DC-biased sinusoidal pattern. However, non-linear characteristic of the magnet produces harmonic components in the magnetic field. The harmonic components are different for each type of magnet depending upon the degree of saturation, and it causes a tracking error. This presentation discussed about precious tracking control between bending and many quadrupole families in J-PARC RCS.
Harada, Hiroyuki
no journal, ,
J-PARC 3-GeV Rapid-Cycling Synchrotron (RCS) is a high-intensity proton driver, which aims the designed beam power of 1MW. RCS beam commissioning has been started since October 2007 and 1MW intensity has been achieved in beam tuning on January 2015. At present, proton beam with beam power of 500kW is delivered to users. In the future, beam power will be gradually increased with carefully monitoring the beam target condition and activation level of accelerator devices. Many beam loss sources were identified by continuously investigating in beam tuning and simulation, and beam loss reduction and intensity ramp-up were achieved. Actually experimental results were reproduced in simulation well. In my presentation, I will introduce RCS and commissioning system, and report the tuning method, experimental and simulation results. Finally, I will suggest beam-commissioning strategy of high intensity synchrotron to accelerator physicists in the world.
Hasegawa, Kazuo
no journal, ,
A major goal of the mini-workshop will be to discuss the commissioning of high intensity accelerators. A broad range of topics to be discussed will include the preparation of commissioning a new project, experience in commissioning existed projects, advanced techniques used in beam diagnostics during machine physics, rules and methods to control the beam loss, etc. At the workshop, commissioning of the linacs for several facilities such as J-PARC, CSNS, C-ADS and SNS will be presented. This talk summarizes the linac part of this workshop.