Applications of vertical damping wigglers in an X-ray diffraction limited storage ring

This study presents a lattice design for an X-ray diffraction limited storage ring (DLSR) light source with a circumference of 864 m and achieving an ultralow natural emittance of 25.6 pm·rad (N-IBS). However, the ultra-low emittance and long damping times lead to significant intra-beam scattering (IBS) effects. To address this issue, the study explores the implementation of vertical damping wigglers (VDWs) to decrease damping times, reduce beam horizontal emittance, and generate vertical emittance to achieve a “round beam” in the 864mDLSR. Through theoretical analysis and accelerator toolbox (AT) simulations, the impacts of VDWs with varied parameters were investigated, and the optimal period length, peak field, and total length were determined. Additionally, the twelve quadrupole magnets in both the front and rear cells of the VDWs were employed to correct linear optics. The findings demonstrate that VDWs could significantly reduce the beam's equilibrium emittance and damping times of the 864mDLSR. Furthermore, a comparison between the spectral brightness and flux of the 864mDLSR with and without VDWs revealed that the 864mDLSR employing VDWs yielded higher brightness and flux. •A lattice of the 864mDLSR was designed with a natural emittance of 25.6 pm·rad.•The VDWs added in the 864mDLSR not only reduced the horizontal emittance but also produce vertical emittance, achieving a “round beam”.•Upon the integration of a total length of 30 m VDWs, the resultant horizontal and vertical emittances were both measured at 9.9 pm·rad.•The spectral brightness of the 864mDLSR augmented eightfold with the incorporation of VDWs as opposed to its counterpart without VDWs.