Speaker
Description
MTCA.4 based LLRF control systems have been developed for synchrotrons of the Japan Proton Accelerator Research Complex (J-PARC). The J-PARC synchrotrons consist of the Rapid Cycling Synchrotron (RCS) and the Main Ring synchrotron(MR). Since the magnetic alloy loaded untuned RF cavity systems are used in both synchrotrons, multi-harmonic amplitude and phase control is essential and required to compensate a heavy beam loading. A MTCA.4 shelf with the DESY-type RF backplane is employed in developed LLRF control system to fit several AMC boards for controlling RF cavities. The multi-harmonic vector RF voltage control function is implemented in AMC to control the cavity RF voltage. The cavity voltage signal for the vector sum calculation and the beam phase feedback signal are exchanged between AMC boards via the MTCA backplane. The LLRF control system for the RCS was successfully deployed in 2019 and contributed to the achievement of stable acceleration of the high-intensity beam up to the design intensity, 8.3e13 protons per pulse. The prototype system for the MR was tested and used in the beam operation since 2020 to suppress unwanted harmonics. We plan to deploy the developed system to the MR during the shut-down period in 2021.
