  Recent developments and validation tests related to the simulation of X-ray
fluorescence and PIXE with Geant4 are reviewed. They concern new models for
PIXE, which has enabled the first Geant4-based simulation of PIXE in a concrete
experimental application, and the experimental validation of the content of the
EADL data library relevant to the simulation of X-ray fluorescence.
Achievements and open issues in this domain are discussed.
