Speaker
Prof.
Grant Ritchie
(University of Oxford)
Description
Atmospheric pressure plasma jets require the highest sensitivity and specificity from diagnostic techniques in order to properly quantify the radical chemistry taking place. In this presentation I will describe several laser based techniques with the necessary capabilities for probing small levels of transient species, and demonstrate how they have been applied to plasma systems. These include optical feedback cavity enhanced absorption spectroscopy and Faraday rotation spectroscopy. Example data on the detection of peroxy radical (RO2) species are presented: HO2 in particular has been highlighted as an important intermediate, implicated in the production of reactive oxygen species in cold atmospheric plasma sources, and is integral to the complex chemical network which generates hydrogen peroxide as one of the by-products. Using convenient technology at near-IR wavelengths, baseline absorption sensitivities have been achieved of the order of a few parts in 10(11), which corresponds to parts-per-billion concentrations within the plasma plume.
Primary author
Prof.
Grant Ritchie
(University of Oxford)
