Measurement of singlet delta oxygen in an atmospheric-pressure helium–oxygen plasma jet. (5th May 2017)

• Record Type: Journal Article
• Authors: Inoue, Yuki; Ono, Ryo
• Is Part Of: Journal of physics. Volume 50:Number 21(2017)
• Publication Date: 2017-05-05
• Subjects: atmospheric-pressure plasma jet -- singlet delta oxygen -- optical emission spectroscopy -- in situ measurement -- absolute density; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/aa6c53
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: The density of singlet delta oxygen O 2 ( a 1 Δ g ) is measured in situ in a He/O2 atmospheric-pressure plasma jet using optical emission spectroscopy at 1.27 μ m. A sinusoidal high voltage of 1–10 kHz is applied between two electrodes wrapped around a quartz tube, in which the working gas flows. The two-dimensional distribution of the O 2 ( a 1 Δ g ) density shows that O 2 ( a 1 Δ g ) is primarily produced in the dielectric barrier discharge inside the quartz tube and that the O 2 ( a 1 Δ g ) production in the plasma jet plume is negligibly small. Typically, 100 ppm of O 2 ( a 1 Δ g ) is produced. The O 2 ( a 1 Δ g ) density increases with O2 concentration and is proportional to the specific input energy (SIE; J/l) irrespective of the discharge voltage, frequency, and gas flow rate. The O 2 ( a 1 Δ g ) production per SIE was 10 ppm/(J/l). The loss processes of O 2 ( a 1 Δ g ) via reactions with O3 and O2 are discussed. The O 2 ( a 1 Δ g ) density decreases when the working gas is humidified. An addition of 200 ppm of H2 O decreases the O 2 ( a 1 Δ g ) density by half.