Update on the use of Geant4 for the Simulation of low-energy protons scattering off X-ray Mirrors at grazing incidence angles

A new physics process has been implemented in the Geant4 Monte Carlo code to treat the scattering of low-energy protons at grazing incidence angles. Experimental data has shown that this is a predominantly surface process where protons are reflected without entering the surface material hence the classical multiple scattering process is not applicable. The new model has been used to revise predictions of proton fluence at the focal plane of the XMM-Newton telescope obtained in earlier simulations.