Analysis and mitigation of bump magnetic field tracking errors in a multiturn injection system

Purpose The Space Environment Simulation and Research Infrastructure (SESRI) is a cluster of accelerators designed to simulate the cosmic radiation environment by generating particles of various types and energies. Among these accelerators, a synchrotron in the 300 MeV proton and heavy ion accelerator complex utilizes a multiturn injection scheme with four bump magnets to accumulate proton and heavy ion beams effectively. However, the bump magnetic field experiences a rapid drop rate of up to 1000 T/s, inevitably leading to a deviation (field tracking error) from the ideal magnetic field. The injection efficiency and particle distribution are significantly affected by this field tracking error, as evaluated by the ACCSIM code. Method During the device testing stage, the sources of field tracking errors were identified by analysis of the bump power supplies and the field of the magnets. Mitigation techniques were then implemented to reduce the field tracking error from ± 35 to ± 1.9% throughout the entire power supply, transmission cable, and magnet chain. Results Moreover, the successful injection and accumulation of beams during the operational phase of the synchrotron confirmed the effectiveness of the proposed mitigation methods. Additionally, a magnetic field measurement system was developed to monitor the magnetic field tracking error online. Conclusion The combination of the field tracking error mitigation methods and the measurement system provides valuable guidance for optimizing the magnetic fields with rapid drop rates.