Development and measurement of a gas temperature controllable atmospheric-pressure plasma jet system for plasma bio research*

In this study, a gas temperature controllable atmospheric-pressure plasma jet (APPJ) system was developed. A quartz tube with a diameter of 10 mm was used to produce a relatively large-sized plume. A special electrode layout, with a ground electrode wrapped outside insulator tape and two floating electrodes, was applied to facilitate easier plasma ignition and enhance the stability of the plasma plume. To make the system applicable to biological tissues, a Peltier unit was employed to decrease the gas temperature. Power dissipation and optical emission spectroscopy (OES) measurements were conducted to assess the performance of the developed APPJ system. The results showed that the inclusion of a floating electrode between the powered and grounded electrodes increased the power dissipation of the plasma, resulting in a brighter plasma bulk region. A floating electrode near the nozzle was found to help the plasma plume extend beyond the nozzle. Additionally, it improved the length of the jets and produced more concentrated jets.