Elucidation of excitation mechanisms which lead to homogeneous and filamentary modes of a dielectric barrier driven plasma-jet
Final Report Abstract
In order to get a reproducible dielectric barrier discharge a square wave generator with slopes steeper than 400 ns / 1000 V was developed and applied to generate the plasma jet. In this case it was not possible to generate any filamentary discharge when He was applied as plasma gas. Therefore, the change of the divergence of the plasma jet during the change of the modes needed not to be investigated. By time and spatially resolved measurements the temporal and spatially change of the plasma could be evaluated. It could be demonstrated that the plasma consists of at three different stages. The plasma jet as well as the early plasma can be observed at nearly the same time at different positions and only in the positive half cycle: the plasma jet outside the discharge capillary and the early plasma in between the two electrodes. After these plasmas the so called coincident plasma will be ignited in between the electrodes. The propagation of the early plasma and that of the coincident plasma are counter propagating and the duration of these plasmas are less than 1 µs when a half period of the cycle is 25 µs. The early plasma as well as the plasma jet is appropriate to fulfill soft ionization while the coincident plasma can be used as dissociative plasma. After the coincident plasma a so called after glow stats between the electrodes. The model system Ar/ammonia for He/N2 was changed into Ar/propane. The heights of the ionization level of propane is comparable with that of ammonia but more appropriate for steel surfaces. It could be demonstrated that the voltage needed to ignite the Ar plasma will reduced to the half when traces of propane are mixed into Ar. The spatial and temporal behavior of the emission signals are comparable with that of the He/N2 system.
Publications
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2016. An experimental study on the influence of trace impurities on ionization of atmospheric noble gas dielectric barrier discharges. Analyst. 141(20):5842-5848
Klute D, Schütz A, Michels A, Vadla C, Veza D, Horvatic V, Franzke J
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2016. Capillary Dielectric Barrier Discharge: Transition from Soft Ionization to Dissociative Plasma. Analytical Chemistry. 88(9):4701-4705
Klute D, Michels A, Schütz A, Vadla C, Horvatic V, Franzke J
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2016. Tuning Soft Ionization Strength for Organic Mass Spectrometry. Analytical Chemistry. 88(10):5538-5541
Schütz A, Klute D, Brandt S, Liedtke S, Jestel G, Franzke J
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2017. Systematic Comparison between Half and Full Dielectric Barrier Discharges Based on the Low Temperature Plasma Probe (LTP) and Dielectric Barrier Discharge for Soft Ionization (DBDI) Configurations. Analytical Chemistry. 89(17):9368-9374
Klute D, Brandt S, Vogel P, Biskup B, Reininger C, Horvatic V, Vadla C, Farnsworth PB, Franzke J
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2018. Characterization of dielectric barrier discharges for analytical chemistry. Journal of Physics D-Applied Physics. 51(31):314003
Klute FD, Schütz A, Brandt S, Burhenn S, Vogel P, Franzke J
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2018. Soft Argon-Propane Dielectric Barrier Discharge Ionization. Analytical Chemistry. 90(5):3537-3542
Schütz A, Lara-Ortega FJ, Klute FD, Brandt S, Schilling M, Michels A, Veza D, Horvatic V, García-Reyes JF, Franzke J
