Human body touchable helium plasma-jet at atmospheric pressure

A novel type of atmospheric pressure, low temperature helium plasma-jet was developed, based on dielectric barrier discharge(DBD), to meet the medical demands. The original work involves the two ring-shaped copper electrodes, 15 mm in diameter and 10 mm in separation, embedded on the upper part of the Tyflon rod with a 2 mm quartz glass tube inserted through the rod s axis and acting as the dielectric barrier and He-path. The electrodes assembly was housed and insulated by a cylindrical Teflon wall. The characteristics of the plasma-jet were diagnosed by evaluating its emission spectra. Moreover, the impact of the plasma irradiation on human skin was modelled, simulated and tested. The results show that the steady, low powered, non-thermal plasma-jet is absolutely safety to human body. To be specific, powered at 4 kV, the contact voltage between the plasma-jet and human body was below 35 V, much lower than the human security voltage. Its properties include a peak discharge current below 7 mA, a discharge power below 1.5 W, a maximum charge transfer about 100 nC; and the active particles include harmless electrons and radicals of OH and O.