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The total electron emission yield (TEEY), at very low energy, is investigated with a Monte Carlo (MC) technique and compared with experimental results. The important points of an MC tool for the simulation of electron emission are presented. The tool is based on a combination of properly selected models taking into account plasmon excitations at the surface and the effect of the crossing surface-barrier potential. The reflectivity is calculated as a function of the primary energy using an analytical expression found in the literature. By comparing MC results with the measurements, a good correspondence between obtained curve shapes is observed. Irregularities in measured and simulated yields are identified and explained by considering plasmon excitations. This comparison allows one, among other things, to remove the ambiguity on the variation of the yield obeying the change in reflectivity as a function of primary energy. In fact, some results reported in the literature claim that the TEEY coefficient approaches unity when the primary electron energy tends to zero. This occurs due to nearly total electron reflection from the surface, for electron energy less than an electron volt. In this paper, we summarize comprehensive studies rendering this claim inaccurate. Aluminum, a free-electron-like metal, will be considered here as a representative illustration. [ABSTRACT FROM AUTHOR]

Secondary electron emission (SEE) is one of the main parameters controlling spacecraft potential. It also plays an important role in the triggering of the multipactor phenomenon occurring in waveguides (electron avalanche in microwave electric fields). In this paper, we propose an original method adapted to low-energy SEE measurements on dielectrics and conductors (incident electron energy below 20 eV). It is based on Kelvin probe (KP) surface potential measurements after electron irradiation. It is particularly well suited to insulating materials but can also be used on metals by letting the sample potential float. We present results of SEE measurements performed on metals used in waveguides, Kapton, Teflon, and CMX cover glass. In order to avoid any experimental artifact due to the earth magnetic field and conduct accurate low-energy measurements with the KP method, the distance between the electron gun and the sample is chosen to be negligible compared to the Larmor radius. [ABSTRACT FROM PUBLISHER]

Abstract: The electron emission due to electron impact of alkali-silicate glasses is measured with a technique based on the use of a Kelvin probe (KP method) and a pulsed electron beam. The KP method, allows a clear discrimination between the external and internal effects of charging process. The effect of the incident charge fluence, incident charge fluency and the temperature on the yield curve is investigated. It was found that, at room temperature as well as at 80°C, electron emission varies with charge fluence. The effects of the temperature on charging mechanisms and charge transport characteristics of alkali-silicate glasses where also studied using the measurement of displacement and leakage currents under continuous electron irradiation in scanning electron microscope (SEM). The results clearly establish a correlation between charge carriers mobility and secondary electron emission yield. The enhancement of charge carrier mobility with increasing the temperature prevents the formation of a positive space charge (i.e. creation of positive ions and/or holes) that internally reduces the secondary electron (SE) emission. The higher is the temperature and the higher is the electron emission yield (EEY). [Copyright &y& Elsevier]