Use of an electron beam for particle charging

The charging performance of an electron beam precharger has been evaluated by measuring the charge acquired by particles with diameters of 1.1 and 3.0 mu m. In the experiment, the beam energy is smaller than the electrode geometry. This avoids spurious ionization by scattered electrons and allows the establishment of a monopolar charging region (by separating the bipolar ions with an electric field). Particle charges greater than the theoretical ionic charging value were observed using the bi-electrode electron beam precharger. The increased charge may be caused by free-electron charging.<
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