In the biomedical applications using low-temperature atmospheric pressure plasmas, charging on surface of the targets could play an important role. In this study, we have investigated potential formed on an electrically floating copper plate treated by a low-temperature atmospheric pressure helium plasma jet. The potential of the copper plate was measured by an electrostatic sensor in a non-contact manner. It was found that the potential on the copper plate could be controlled from 200 to −600 V by changing the distance between the nozzle of plasma device and the surface of copper plate. We discussed the charging mechanism such as collection of charged particles and several processes of electron emission including thermionic, field emission, secondary electron emission, and photoelectric processes.

在使用低温大气压等离子体的生物医学应用中，目标表面的充电可能发挥重要作用。在这项研究中，我们研究了在低温大气压氦等离子体射流处理的电浮铜板上形成的电位。铜板的电位通过静电传感器以非接触方式测量。发现通过改变等离子装置喷嘴与铜板表面之间的距离，可以将铜板上的电位控制在200～-600 V。我们讨论了充电机制，例如带电粒子的收集和电子发射的几个过程，包括热离子、场发射、二次电子发射和光电过程。