An experimental study on the influence of trace impurities on ionization of atmospheric noble gas dielectric barrier discharges

Abstract

While the influence of trace impurities in noble gas discharges is well established in theoretical work, experimental approaches are difficult. Particularly the effects of trace concentrations of N on He discharges are complicated to investigate due to the fact that for He 5.0 the purity of He is only 99.999%. This corresponds to a residual concentration of 10 ppm, thereof 3 ppm of N, in He. Matters are made difficult by the fact that He DBD plasmajets are normally operated under an ambient atmosphere, which has a high abundance of N. This work tackles these problems from two sides. The first approach is to operate a DBD plasmajet under a quasi-controlled He atmosphere, therefore diminishing the effect of atmospheric N and making a defined contamination with N possible. The second approach is using Ar as the operating gas and introducing propane (CH) as a suitable substitute impurity like N in He. As will be shown both discharges in either He or Ar, with their respective impurity show the same qualitative behaviour.

Numerical simulation of capillary helium and helium−oxygen atmospheric pressure plasma jets: propagation dynamics and interaction with dielectric

“…From [19], it was also observed that there is a minimum threshold for the helium mole fraction in the helium jet for the successful propagation of the plasma bullet. Recently many important experimental studies have been carried out providing very good insight into the characterization and understanding of these devices, the electric fields [20][21][22][23][24][25] and the different produced species [26][27][28][29][30][31]. However, in order to increase the understanding behind the operation of APPJ and to overcome some of the practical experimental limitations, numerical modelling has been increasingly used to simulate APPJ devices.…”

Flexible Microtube Plasma (FμTP) as an Embedded Ionization Source for a Microchip Mass Spectrometer Interface

“…In addition to atmospheric pressure chemical ionization (APCI), dielectric barrier discharges (DBDs) have become a suitable ionization source for several types of applications. − In addition to having soft ionization capabilities, these discharges can also be used for atomic absorption spectroscopy (AAS) and optical emission spectroscopy (OES) when modified. − Thus, DBDs are highly versatile. Detailed studies have increased knowledge about fundamental discharge mechanisms in noble gas discharges at atmospheric pressure, which have led to further improvements in the use of these discharges. , Flexible microtube plasma (FμTP), being a small, easy, and safe-to-handle discharge, is the result of this optimization. Because of its small dimensions and flexible nature, it can be incorporated without major effort into existing setups.…”

“…Detailed studies have increased knowledge about fundamental discharge mechanisms in noble gas discharges at atmospheric pressure, which have led to further improvements in the use of these discharges. 24,25 Flexible microtube plasma (FμTP), being a small, easy, and safe-tohandle discharge, is the result of this optimization. Because of its small dimensions and flexible nature, it can be incorporated without major effort into existing setups.…”

Analyte-Tailored Controlled Atmosphere Improves Dielectric Barrier Discharge Ionization Mass Spectrometry Performance

“…Adding other reaction or collision partners leads to different reactions, and the minimum ignition voltage will change. Other mechanisms resulting in, e.g., the protonation of analyte molecules, are also interfered by these changes 24 .…”