Digitization modeling of a CGEM detector based on Garfield++ simulation

The Cylindrical Gas Electron Multiplier Inner Tracker (CGEM-IT) is one of the candidates for the replacement of the current BESIII inner drift chamber, which has developed serious aging effects due to beam-related backgrounds. To build a full digitization model, it is necessary to understand the electron drift behavior and signal induction. A simulation study based on Garfield++ and ANSYS software has been performed. Parameters describing the Lorentz angle, diffusion effect, drift time, multiplication, and induction are obtained from the Garfield++ simulation. Based on these results, a preliminary digitization model is implemented in the BESIII offline software system.