Performance of AC-LGAD strip sensor designed for the DarkSHINE experiment

AC-coupled Low Gain Avalanche Detector (AC-LGAD) is a new precise detector technology developed in recent years. Based on the standard Low Gain Avalanche Detector (LGAD) technology, AC-LGAD sensors can provide excellent timing performance and spatial resolution. This paper presents the design and performance of several prototype AC-LGAD strip sensors for the DarkSHINE tracking system, as well as the electrical characteristics and spatial resolution of the prototype sensors from two batches of wafers with different $n^{+}$ dose.The range of spatial resolutions of 6.5$\mu \mathrm{m}$ $\sim$ 8.2$\mu \mathrm{m}$ and 8.8$\mu \mathrm{m}$ $\sim$ 12.3$\mu \mathrm{m}$ are achieved by the AC-LGAD sensors with 100$\mu m$ pitch size.