High-Precision 4D Tracking with Large Pixels using Thin Resistive Silicon Detectors

TL;DR

This paper demonstrates high-precision 4D tracking using large-pixel resistive silicon detectors, achieving excellent spatial and temporal resolutions through charge sharing and electrode design improvements.

Contribution

It introduces a new characterization and reconstruction method for resistive silicon detectors with large pixels, achieving sub-20 ps timing and 15-micron spatial resolutions.

Findings

450 x 450 microns^2 pixel achieves 20 ps timing and 15 microns spatial resolution.

Large pixels up to 1300 x 1300 microns^2 maintain good resolution with 30 ps and 30 microns.

Cross-shaped electrodes improve response uniformity across the pixel surface.

Abstract

The basic principle of operation of silicon sensors with resistive read-out is built-in charge sharing. Resistive Silicon Detectors (RSD, also known as AC-LGAD), exploiting the signals seen on the electrodes surrounding the impact point, achieve excellent space and time resolutions even with very large pixels. In this paper, a TCT system using a 1064 nm picosecond laser is used to characterize sensors from the second RSD production at the Fondazione Bruno Kessler. The paper first introduces the parametrization of the errors in the determination of the position and time coordinates in RSD, then outlines the reconstruction method, and finally presents the results. Three different pixel sizes are used in the analysis: 200 x 340, 450 x 450, and 1300 x 1300 microns^2. At gain = 30, the 450 x 450 microns^2 pixel achieves a time jitter of 20 ps and a spatial resolution of 15 microns concurrently, while the 1300 x 1300 microns^2 pixel achieves 30 ps and 30 micron, respectively. The implementation of cross-shaped electrodes improves considerably the response uniformity over the pixel surface.