An atmospheric plasma source for seed treatment and biological decontamination
Résumé
Atmospheric plasma treatment can affect growth and physiology of plants. Some recent works on seeds shown modifications of the surface properties and stimulation of seed germination. A plasma exposure can also have biocidal or fungicidal effects on seeds.
In this preliminary work, an atmospheric multiple points plasma source has been developed. The source is composed by thousands of points arranged in concentric circles. The diameter is approximately 90 mm. The power supply is a DC one generating 35 kV and 1 mA (max values). The voltage is applied to the multiple points. The ground is connected to the substrate (conductive grid). The plasma is generated in ambient air between the multiple points and the conductive grid. The experimental set-up is presented on Figure 1. For plasma treatment, the samples could be placed on the grid (direct treatment) or under the grid (indirect treatment using the ionic wind generated by the discharge.
First, the current characterization as a function of voltage was performed to characterize the plasma source.
Next spatial optical emission distribution measurements were performed with an optical spectrometer (HR2000+, Ocean Optics) from the emission spectra for the main observed species. In a preliminary work, this source was used to evaluate the plasma effect on different seed properties and seed germination. The seeds were directly in contact with the plasma or exposed to the ionic wind generated by the multiple discharges.
In this preliminary work, an atmospheric multiple points plasma source has been developed. The source is composed by thousands of points arranged in concentric circles. The diameter is approximately 90 mm. The power supply is a DC one generating 35 kV and 1 mA (max values). The voltage is applied to the multiple points. The ground is connected to the substrate (conductive grid). The plasma is generated in ambient air between the multiple points and the conductive grid. The experimental set-up is presented on Figure 1. For plasma treatment, the samples could be placed on the grid (direct treatment) or under the grid (indirect treatment using the ionic wind generated by the discharge.
First, the current characterization as a function of voltage was performed to characterize the plasma source.
Next spatial optical emission distribution measurements were performed with an optical spectrometer (HR2000+, Ocean Optics) from the emission spectra for the main observed species. In a preliminary work, this source was used to evaluate the plasma effect on different seed properties and seed germination. The seeds were directly in contact with the plasma or exposed to the ionic wind generated by the multiple discharges.