The performance of large-pitch AC-LGAD with different N+ dose

TL;DR

This study investigates how varying N+ doping doses affect the spatial and time resolution of large-pitch AC-LGAD detectors, revealing that lower doses improve spatial resolution without significantly impacting timing jitter.

Contribution

It provides experimental insights into the impact of N+ dose variations on large AC-LGAD performance, a novel exploration for large-size detectors.

Findings

Spatial resolution improved from 36 to 16 micrometers with lower N+ dose.

Time jitter remained stable around 15-17 ps across doses.

Lower N+ dose resulted in larger signal attenuation and better spatial resolution.

Abstract

AC-Coupled LGAD (AC-LGAD) is a new 4D 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~\SI{}{\micro\metre} and AC pad of 1000~\SI{}{\micro\metre}, and explored the effect of N+ layer dose on the spatial resolution and time resolution. The spatial resolution varied from 36~\SI{}{\micro\metre} to 16~\SI{}{\micro\metre} depending on N+ dose for a charge corresponding to about 12 minimum ionizing particles. 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 factor and low noise level are beneficial to improve the spatial resolution of the AC-LGAD sensor.