Based on knowledge in the field of physics of electron-gas interactions and simulations of these phenomena, our MC software for ESEM will be adapted to a higher speed and accuracy of simulations, especially thanks to an optimised algorithm and the possibility to direct integration of precise gas flow data. The data will be counted using the enhanced mathematical model for ANSYS Fluent software, realized in the project. Simulation results will be tested in the design of a new differentially pumped part of the ESEM objective and high-efficiency detection systems. New designs will be targeted towards increasing ESEM resolution and recording the secondary electron signal emitted under low beam energy and low beam current, high scanning speeds and gas pressure. Project outcomes support basic research of the co-applicant focused on the morphological characterisation of susceptible wet samples in their native state with high resolution and study of their changes in dynamic in situ experiments.