Speaker
Description
To meet the requirements of enhanced radiation tolerance and sustained tracking performance, the BESIII inner tracker has been upgraded to a Cylindrical Gas Electron Multiplier (CGEM). We have developed a comprehensive simulation framework for the CGEM response, featuring a realistic digitization model refined with experimental data. The framework simulates the full signal-formation chain (ionization, drift, multiplication, induction, and readout) and explicitly incorporates detector structural effects such as GEM foil sectorization and support grids. Key model parameters have been tuned against both cosmic-ray and collision data, and computational efficiency has been optimized. The tuned model shows good agreement with measurements, providing a reliable basis for detector calibration, alignment, tracking studies, and subsequent physics analyses.