Experimental studies on low-pressure air dielectric barrier discharge plasma for ionization source

This study experimentally investigates the properties of low-pressure dielectric barrier discharge (DBD) plasma. A ring-ring DBD configuration was employed. Spectroscopic and electrical measurements were conducted at varying gas pressures to characterize the plasma properties. The results revealed that the luminous region of the plasma expands and exhibits maximum luminescence near 600 Pa, with a subsequent contraction and intensity diminution at lower pressures. Analysis of emission spectra identified nitrogen's second positive system (SPS) and first negative system (FNS) as the primary contributors. The highest density of excited molecule $N_2\left(C^3{\Pi }_u\right)$ and excited ion $N_2^{+}\left(B^2{\Sigma }_u^{+}\right)$ are at 660 Pa and 100 Pa, respectively. Mass spectrometry measurements indicate that the excited state $N_2\left(C^3{\Pi }_u\right)$ has the ability to undergo Penning ionization. This study provides the variation of excited molecules and ions with pressure in low-pressure dielectric barrier discharge, which can be used for the optimization of ionization source and the analysis of mass spectrometry data.