Development And Testing Of LLRF Based On Pulse Mode

The ion beam provided by the ion source requires an accelerator through the cyclotron to achieve the appropriate beam intensity for subsequent scientific research,which provides technical support for accelerator-driven advanced nuclear energy system applications.The main part of the cyclotron is cavity.The low level system LLRF(Low Level Radio Frequency)aims to control the cavity to work in the resonance state under the condition of large beam load and strong Lorentz force detuning to reducing the rolling fluctuation.The effects of temperature,cavity deformation and noise on the tuning process ensure that the beam that reaches the target is drawn.The function of the low level based of pulse mode is to achieve the automatic feedback control to the system by controling the voltage and phase of the cavity.This paper firstly investigates the international low-level control system and combines the advantages of different schemes to determine the overall layout of the system and the loop control scheme,and then introduces the pulse LLRF in the analog RF front-end,digital signal processing two parts from The design of the hardware and software to the implementation process,and improved the previous generation low-level part of the algorithm,reducing the impact of noise on the IF signal,to ensure measurement accuracy.Finally,the pulse LLRF is verified by function and test tuning.The obtained laboratory data is analyzed by a complete test loop.The amplitude and phase stability of the cavity voltage are within the error tolerance.which achieve the control accuracy requirements.The development and debugging process of the pulse LLRF provides experience and research direction for the low-level system working in complex control environment in the future.