Simulation of MAPS and a MAPS-based Inner Tracker for the Super Tau-Charm Facility

TL;DR

This paper presents a simulation study of MAPS sensors and a MAPS-based inner tracker for the Super Tau-Charm Facility, demonstrating high detection efficiency and excellent spatial resolution through detailed modeling and optimization.

Contribution

It introduces a dedicated simulation workflow for MAPS performance evaluation and proposes an optimized MAPS sensor design for the STCF inner tracker.

Findings

Detection efficiency exceeds 99%.

Spatial resolution is 44.8 μm (z) and 8.2 μm (r-phi).

Sensor time resolution is 5.9 ns for 1 GeV/c muons.

Abstract

Monolithic Active Pixel Sensors (MAPS) are a promising detector candidate for the inner tracker of the Super Tau-Charm Facility (STCF). To evaluate the performance of MAPS and the MAPS-based inner tracker, a dedicated simulation workflow has been developed, offering essential insights for detector design and optimization. The intrinsic characteristics of MAPS, designed using several fabrication processes and pixel geometries, were investigated through a combination of Technology Computer Aided Design (TCAD) and Monte Carlo simulations. Simulations were conducted with both minimum ionizing particles and $^{55}$Fe X-rays to assess critical parameters such as detection efficiency, cluster size, spatial resolution, and charge collection efficiency. Based on these evaluations, a MAPS sensor featuring a strip-like pixel and a high-resistivity epitaxial layer is selected as the baseline sensor design for the STCF inner tracker due to its excellent performance. Using this optimized MAPS design, a three-layer MAPS-based inner tracker was modeled and simulated. The simulation demonstrated an average detection efficiency exceeding 99%, spatial resolutions of 44.8$\rm{\mu m}$ in the $z$ direction and 8.2$\rm{\mu m}$ in the $r-\phi$ direction, and an intrinsic sensor time resolution of 5.9ns for 1GeV/c $\mu^-$ particles originating from the interaction point. These promising results suggest that the MAPS-based inner tracker fulfills the performance requirements of the STCF experiment.