ABSTRACT
A hairpin resonance probe was used firstly to monitor the radio-frequency-driven He or He/O2 atmospheric pressure plasma jet. The reflected microwave spectrum from the probe was recorded by a vector network analyzer. Nonthermal atmospheric pressure plasma and atmospheric pressure plasma jet have gained much more focus recently due to its potential applications in material processing. Many diagnostic techniques such as the Langmuir probe, microwave resonant probe and light absorption have been widely applied in low pressure plasmas, these techniques are rarely used for atmospheric pressure plasma especially for plasma jet as most of them become useless at higher pressure. The rf-atmospheric pressure plasma jet (APPJ) source is generated by AtomfloTM 250 plasma applicator. High pressure plasma because of p the hairpin robe remains the same when it is immersed resonant frethe resonance width normalized by into the Figure Optical emission spectra the helium rf-APPJ.
