The Performance of Large-Pitch AC-LGAD With Different N+ Dose

AC-coupled LGAD (ac-LGAD) is a new 4-D detector developed based on the low-gain avalanche diode (LGAD) technology, which can accurately measure the time and spatial information of particles. The Institute of High Energy Physics (IHEP) designed a large-size ac-LGAD with a pitch of
$2000~\mu \text{m}$
and ac pad of
$1000~\mu \text{m}$
and explored the effect of N+ layer dose on the spatial resolution and time resolution. The spatial resolution varied from 36 to
$16~\mu \text{m}$
depending on N+ dose for a charge corresponding to about 12 minimum ionizing particles (MIPs). The jitter component of the time resolution does not change significantly with different N+ doses, and it is about 15–17 ps measured by laser. The ac-LGAD with a low N+ dose has a large attenuation factor and better spatial resolution in the central region between pads. In these specific conditions, large signal attenuation factors and low noise levels are beneficial to improve the spatial resolution of the ac-LGAD sensor.