A cold-cathode closed-drift ion source includes an anode, a cathode and a power supply. In certain example embodiments, neither the positive nor negative terminals of the power supply are connected to ground, and the anode and cathode are also not connected to ground. Thus, the ion source operates in a floating mode. As a result, the likelihood of formation of a problematic secondary circuit from the source to the power supply through the walls can be reduced and/or eliminated (or suppressed). Therefore, the chance of drawing a net positive charge from the ion source which induces a positive charge on dielectric or other surfaces proximate the wall(s) can be suppressed and/or reduced.