Nonlinear dynamic optimization of CEPC booster lattice

Aims: In September 2012, Chinese scientists proposed a circular electron positron collider (CEPC) at 240 GeV center of mass for Higgs studies. The CEPC booster (CEPCB) provides 120 GeV electron and positron beams to the CEPC collider. Methods: The phase-shift-optimizing method is proposed and used in the CEPC booster design. We also explain the physics picture of this method, and then some numerical results are listed to confirm our idea. Result: With the phase-shift-optimizing method, the dynamic aperture increases in varying degrees, especially for off-momentum particles. Conclusions: In this paper, we find out the key point of CEPC booster lattice design. Using phase-shift-optimizing method, a CEPC booster lattice design with good dynamic aperture is given. © 2017, Institute of High Energy Physics, Chinese Academy of Sciences; China Nuclear Electronics and Nuclear Detection Society and Springer Nature Singapore Pte Ltd.