Validation of a Geant4 full model for the MIXS instrument at BepiColombo

A full Geant4 model for the BepiColombo MIXS X-ray telescope has been implemented in order to simulate the propagation of fluorescence X-rays through a state-of-the-art micro channel optics (MCP). Our model includes a realistic 3D geometrical description of the instrument, down to micrometer scale for the optics, as well as the physics processes for the reflection of X-ray photons at grazing angles combined with the standard Geant4 electromagnetic interactions. The model has been preliminary validated against design reference simulation software and with experimental test data.