Lattice design for a hybrid multi-bend achromat light source

We present a lattice design and beam dynamics analysis for a 4 GeV low-emittance, high-brilliance synchrotron light source. The lattice consisted of 26 six-bend achromats with 26 long and 26 short straight sections. We present the design results for a hybrid multi-bend achromat (HMBA) lattice with a natural emittance of 168 pm and circumference of 729.3 m. Each cell had 4 longitudinal gradient bendings, 2 combined bendings, 14 quadrupoles, and 2 families of sextupoles. The lattice was designed to be flexible to provide both nonzero and zero dispersion functions in the long straight section. The two straight sections in each cell had lengths of 5.6 and 1.2 m. To ensure sufficient injection, we optimized the design lattice and dynamic aperture. We investigated the dynamic aperture in the lattice with machine errors, and the results showed that the lattice design provides sufficient dynamic aperture after COD correction for beam injection. We present the results of an injection scheme that demonstrates the space in the injection section and the particle motions of the injected beam. We also present the results of beam tracking after the beam injection to examine the characteristics of the beam injection. The designed HMBA lattice was well optimized in terms of the beam parameters and brilliance as an intermediate light source at 4 GeV and a circumference of 729.3 m.