Implementation of the code for the simulation of the response of a triple-GEM tracker and its comparison to the experimental data

In the framework of detector development, Monte Carlo simulations play a key role in the evaluation of the expected performance and the full understanding of the behavior in beam conditions. In particular, a software which simulates the response of the detector to the particle passage is mandatory to test different setups and solutions, such as geometries, fields, voltages etc. and to understand the test beam data. For gas trackers, existing softwares, such as GARFIELD, perform a very detailed simulation of the physical processes but are also CPU time consuming. For the new cylindrical GEM tracker of BESIII, a faster code which models the results obtained from GARFIELD and adapts them to the experimental data, collected in several test beams, has been written. It reproduces the behavior of a planar triple-GEM under different working conditions and, when completed, it will be inserted in the official code of BESIII. A description of the procedure, based on different components (ionization, diffusion and magnetic field, avalanche multiplication, signal induction and readout) will be given and its results will be compared to the GARFIELD simulations and to the experimental data.