Variation of ozone reflection coefficient at a metal surface with its gradual oxidation

Investigation of ozone loss rate in a metallic chamber has been performed paying attention to the wall materials effect. Stainless steel, copper, and aluminum are used in the experiments. Ozone is produced by corona discharge electrode, which was mounted on the secondary electrode of a piezoelectric transformer. The decaying ozone density, which was observed after the corona discharge interruption, was measured using the HgI 254 nm photo absorption method. The temporal decrease of ozone density shows a single-exponential and the loss rates of ozone, that is, the inverse of ozone lifetimes are determined. During the experiment with repetition using the same surface material, we found a gradual increase of the ozone reflection coefficient in the low-pressure region. We adopted surface inspection of specimens using electron probe micro analysis (EPMA), Auger electron spectroscopy (Auger), and X-ray photoelectron spectroscopy (XPS). The results indicate that some amount of oxygen atoms is detected in the surface layer of the specimen. We consider that the increase of ozone reflection coefficient with the repeated measurement corresponds to gradual oxidation of the surface wall material.