Two-plane painting injection scheme for BRing of HIAF

The high-intensity heavy-ion accelerator facility (HIAF) is under design at the Institute of Modern Physics (IMP) and will provide an intense ion beam for nuclear physics,atomic mass measurement research,and other applications.As the main ring of HIAF,the BRing accumulates beams to high intensity and accelerates them to high energy.To achieve high intensities up to 1 × 1011 (238U34+),the injection gain of the BRing must be as high as 88.However,multiple multiturn injection supported by the electron cooling system takes a long time,causing substantial beam loss under a strong space charge effect.Hence,a two-plane painting injection scheme is proposed for beam accumulation in the BRing.This scheme uses a tilted injection septum and horizontal and vertical bump magnets to paint the beam into horizontal and vertical phase space simultaneously.In this paper,the two-plane painting injection parameters are optimized,and the resulting injection process is simulated using the Objective Ring Beam Injection and Tracking (ORBIT) code.An injection gain of up to 110.3 with a loss rate of 2.3％ is achieved,meeting the requirements of BRing.