Design Study for the First Version of the HALS Lattice

The Hefei Advanced Light Source (HALS) was proposed as a future soft X-ray diffraction-limited storage ring at NSRL. Recently the first version lattice of the HALS storage ring has been studied using a new lattice design concept that we proposed for diffraction-limited storage rings. In this new concept, the beta functions of each cell are made to be locally symmetric. In this paper, an 8BA lattice and a 6BA lattice are designed for the HALS with the first and the second kind of the new concept, respectively. In their nonlinear optimization, good dynamic aperture and momentum aperture can be easily obtained. Especially the dynamic momentum aperture can be larger than 7% or even 10%, which enables long beam lifetime and implementation of longitudinal injection scheme. The studied 6BA lattice is at present considered as the nominal HALS lattice of the first version.