Application of the 2D/3D MICHELLE code to electron gun and collector modeling

The focus of the development program is to combine modern finite element techniques with improved physics models. The code employs a conformal mesh, including both structured and unstructured mesh architectures for meshing flexibility, along with a new method for accurate, efficient particle tracking. New particle emission models for thermionic beam representation are included that support primary emission, and secondary emission is handled with an advanced model.