Analyzing atomic oxygen product evolution in micro cavity plasma arrays by a combination of a multi-PMT OES setup and a 0D chemical model

Dielectric barrier discharges (DBDs) are widely used in applications such as ozone generation and volatile organic compound treatment, where performance can be enhanced through catalyst integration. A fundamental understanding of reactive species generation is essential for advancing these technologies. However, temporally resolving reactive species production especially during the initial discharges remains a challenge, despite its importance for controlling production rates and energy efficiency. This study examines atomic oxygen production as a model system for reactive species production in a micro-cavity plasma array, a custom surface DBD confined to micrometer-sized cavities. Optical emission spectroscopy was employed to investigate plasma-chemical processes in helium with 0.1%-0.25% molecular oxygen admixture at atmospheric pressure. The discharge, powered by a 15 kHz, 600 V amplitude triangular voltage, achieved near-complete oxygen dissociation (up to 100%), as determined via helium state-enhanced actinometry. A novel multi-photomultiplier system enabled precise temporal tracking of atomic oxygen density and dissociation dynamics. To ensure measurement accuracy, a basic 0D chemical model was developed, reinforcing the reliability of the experimental results.