  Gas Electron Multiplier (GEM)-based detectors using a layer of 10B as a
neutron converter is becoming popular for thermal neutron detection. A common
strategy to simulate this kind of detector is based on two frameworks: Geant4
and Garfield++. The first one provides the simulation of the nuclear
interaction between neutrons and the 10B layer, while the second allows the
simulation of the interaction of the reaction products with the detector gas
leading to the ionization and excitation of the gas molecules. Given the high
ionizing power of these nuclear reaction products, a full simulation is very
time consuming and must be optimized to become viable. In this work, we present
a strategy to develop a fast simulator based on these two frameworks that will
allow us to generate enough data for a proper evaluation of the expected
performance and optimization of this kind of detector. We will show the first
results obtained with this tool concentrating on its validation and
performance.
