Optimisation of secondary electron detector for variable pressure SEM with Monte Carlo method

A computer programme for numerical modelling of electron flow in vacuum instruments is presented. The programme allows to simulate trajectories of charged particles in both high and low vacuum of the order of tens milibars. It combines a commercially available packet SIMION 3D v.7.0 destined for tracing trajectories of charged particles in electric and magnetic fields, and a Monte Carlo programme modelling phenomena accompanying electron collisions with gas molecules. The programme was applied for analysis and optimisation of a novel secondary electron detector for a variable-pressure scanning electron microscopy.