Model of secondary emission and its application on the charging of gold dust grains

摘要

We present a combined experimental and simulation study of the charging of the spherical gold samples by an electron beam in a 0.15-10 keV range of beam energies. Experiments on grains with diameters of the order of 10~(-6) m show that the charge (or surface potential) of grains levitating in a guadrupole trap is a function of both grain diameter and beam energy. Monte Carlo simulations reveal that an increase of the grain potential with the beam energy for a fixed diameter or a surface potential decrease with the grain diameter for a given beam energy are connected with changes of the relative number of backscattered primary electrons. The results of simulations are in a good quantitative agreement with previously published as well as our fresh experimental data.