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

The DarkSHINE experiment proposes a novel approach to single-electron-on-fixed-target exploration that focuses on the search for dark photons through their invisible decay into dark matter particles. Central to this initiative is an advanced tracking detector designed to achieve exceptional sensitivity in the detection of light dark matter candidates. This study evaluates the performance of several prototype AC-coupled low-gain avalanche diode (AC-LGAD) strip sensors specifically developed for the DarkSHINE tracking detector. The electrical properties of the sensors from two batches of wafers with different \(\text {n}^+\) ${\text{n}}^{+}$ doses are thoroughly evaluated. Spatial and temporal resolutions are measured using an infrared laser source. The spatial resolutions range from 6.5 to 8.2  \(\mathrm {\upmu m}\) $\mathrm{\mu }\mathrm{m}$ and from 8.8 to 12.3  \(\mathrm {\upmu m}\) $\mathrm{\mu }\mathrm{m}$ for the sensors from two distinct dose batches, each with a 100  \(\mathrm {\upmu m}\) $\mathrm{\mu }\mathrm{m}$ pitch size. Furthermore, the sensors demonstrate time resolutions of 8.3 and 11.4 ps, underscoring the potential of AC-LGAD technology in enhancing the performance of the DarkSHINE tracking detector.