The purpose of this study is to analyse the response of a single HEXITEC detector system when it is exposed to complex radiation fields such as proton beam therapy and evaluate its feasibility to tackle the uncertainty in the proton range via secondary particle detection. For the present research, experimental data is taken in a clinical proton beam therapy room at different nominal proton energies, where a water phantom is irradiated and a HEXITEC detector is placed on one side. The results of the detector output are compared with simulations performed on Geant4, which include additional information about the particles entering the detector such as particle type, kinetic energy and parent ID. The resulting comparison shows that the computational model can simulate the experimental data with a high level of accuracy. In terms of particle flux, there is a consistent agreement between simulation and experimental data. In addition, a relationship between experimental and modelled acquisition frames is achieved. Particle discrimination can be done by performing a cluster size analysis for each particle type.