For the realistic simulation of electron sources using field emitter arrays, the sub-micron resolution required for the emitters leads to simulation models not suitable for current serial codes. Thus, a parallel high-performance 3D Particle-In-Cell code, called Capone, has been implemented in C++ using the POOMA II framework on the Linux platform. Sophisticated C++ expression templates techniques deliver Fortran performance combined with high-level programming and development comfort. For the computation of external fields, matching parallel field solvers are in development with the electrostatic one being completed.The Maxwell field solver is based on the Finite Integration Algorithm on a non-uniform rectilinear grid. Anisotropic ε and μ constants and perfect electric/magnetic materials stored in triangulated grid cells are supported as well as open, electric and magnetic boundary conditions. Self-consistent macro-particle pushing is accomplished by integrating the classical relativistic equations of motion in combination with charge-conserving current scattering onto the computational grid.Parallelization is performed by partitioning the calculation domain into patches associated to individual processors. Fields are statically distributed while Particles are concurrently distributed to processors according to their position to allow fast local interpolation.