Slow extraction system for booster ring at HIAF

The HIAF (High Intensity heavy ion Accelerator Facility) project, proposed by the Institute of Modern Physics (IMP) of Chinese Academy of Sciences, has entered the preliminary design stage. As the key accelerator of the HIAF complex, the Booster Ring (BRing) can accumulate ²³⁸U³⁵⁺ beam up to 1.0×10¹¹ particles per pulse using two plane painting injection scheme, and accelerate it from injection energy of 17 MeV/u to high extraction energy range of 200-835 MeV/u. To provide quasi-continuous beam in several seconds for irradiation and some special nuclear physics experiments, slow extraction system has been designed. The third order resonance and RF-knockout extraction scheme will be adopted for the slow extraction system. Two kinds of sextupoles in the synchrotron, for correcting chromaticity and driving resonance, are considered to be orthogonal. This paper discusses the simulation results for the large and the small stable acceptance in the BRing and presents the optical parameters at the electrostatic septum ESe1 for different extraction energies of the ²³⁸U³⁵⁺ beam. It can provide important theoretical base for slowly extracted heavy ion beams from the BRing, and for the entrance lattice design of HIAF FRagment Separator (HFRS).