Characterization of BNL and HPK AC-LGAD sensors with a 120 GeV proton beam

TL;DR

This study evaluates AC-LGAD sensors from BNL and HPK using 120 GeV protons, demonstrating advanced position and time resolutions surpassing previous binary readout capabilities.

Contribution

It provides the first demonstration of silicon sensors achieving sub-10 micron position and 30 ps time resolution in a test beam setting.

Findings

Achieved better than 6-10 micron position resolution.

Achieved 30 ps time resolution.

Compared performance across different manufacturers.

Abstract

We present measurements of AC-LGADs performed at the Fermilab's test beam facility using 120 GeV protons. We studied the performance of various strip and pad AC-LGAD sensors that were produced by BNL and HPK. The measurements are performed with our upgraded test beam setup that utilizes a high precision telescope tracker, and a simultaneous readout of up to 7 channels per sensor, which allows detailed studies of signal sharing characteristics. These measurements allow us to assess the differences in designs between different manufacturers, and optimize them based on experimental performance. We then study several reconstruction algorithms to optimize position and time resolutions that utilize the signal sharing properties of each sensor. We present a world's first demonstration of silicon sensors in a test beam that simultaneously achieve better than 6-10 micron position and 30 ps time resolution. This represents a substantial improvement to the spatial resolution than would be obtained with binary readout of sensors with similar pitch.