This is an electronic version of the paper presented at the 5th International Workshop on Multipactor, Corona and Passive Intermodulation In Space RF Hardware, held in Noordwijk on 2005In the context of the ESA Program AO 4025 Surface Treatment and Coating, we have developed a simulator called
MEST for the prediction of the multipactor effect. The simulator has been developed using a micro level object-oriented
approach, where each electron in the simulation is an independent object. This approach differs from other models
described in the literature, which are macro level or intermediate, handling electrons in packages rather than
individually. MEST works with a simplified model of a waveguide, where a radiofrequency potential is applied to the
plates. The space between the plates is assumed to be a vacuum, except for the presence of a number of free electrons.
The individual trajectories of all the electrons in the RF field are computed, although no space charge effects are
assumed. When electrons collide with the plates, secondary emission of electrons is simulated. The secondary electron
emission yield (SEY) is computed with a detailed Monte Carlo model, which has been validated using experimental
data. It depends on the surface material (bulk), but also on surface finish properties, such as air contamination,
cleanliness or surface treatments. If certain conditions hold, the number of electrons between the plates may increase
out of control, until a multipactor discharge occurs and the waveguide becomes unusable. The object of the simulator is
to predict the occurrence (or not) of this phenomenon for different surface materials. The simulator has been validated
using experimental data from ESTEC (ESA), UAM and TESAT. Several materials have been tested. The results show
good agreement with the experimental dat