Beam dynamics in the booster synchrotron of Korea-4GSR project

In recent years, there have been several projects in the world to design and construct a diffraction-limited light source which pushes an emittance of electron beams in a storage ring close to an emittance of photon beams in the X-ray region to enhance brilliance by two orders of magnitude. In line with this trend, the Korea fourth-generation storage ring (Korea-4GSR) project was launched in 2021 to establish a new light source in the Republic of Korea with an ultra-low emittance of 50 pmrad at a beam energy of 4 GeV. For the Korea-4GSR project, a compact linear accelerator for generating 200 MeV and a booster synchrotron is chosen as an injector. The booster synchrotron ramps beam energy from 200 MeV to 4 GeV and the lattice is designed based on the FODO concept. It is crucial in the booster to achieve high beam quality for injection efficiency into a storage ring. Since the quality of the extracted beam relies on an energy ramping profile, the ramping process is important to be optimized. This paper represents the result of our studies on the effect of the energy ramping profile in the evolutionary physical process in a booster synchrotron.