Atmospheric pressure plasma jets (APPJs) are operating in direct contact with dielectric substrates for many applications. Nonetheless, many studies have been focusing on free jets. In this letter, we report spatially resolved measurements of reactive species including neutral and ionic species in an He + 1% O2 RF-driven APPJ by molecular beam mass spectrometry equipped with a dielectric sampling plate, enabling to detect species densities for APPJ operating remotely or in direct contact with a substrate. The spatially resolved distribution of O, O2(a 1Δg) and O3 is dominated by convection and, remarkably, shows minimum differences between touching and non-touching conditions.
- ion flux
- molecular beam mass spectrometer
- reactive species density
- touching and non-touching atmospheric pressure plasma jets