Laser-Induced Fluorescence Measurements of Atomic Oxygen Using Two Calibration Methods

摘要

Number densities of atomic oxygen have been measured in pure oxygen plasma, using two-photon laser-induced fluorescence measurements. In this paper, two calibration techniques are compared: the sensitivity of the experimental setup is calibrated using scattering experiments, and reference measurements on xenon are performed using two-photon laser-induced fluorescence measurements. The theoretical background and the experimental setup are described in detail. The advantages and drawbacks are herewith outlined. Applied to high-enthalpy, pure oxygen plasma, the evaluated number densities show fairly good agreement; however, because a constant discrepancy is measured between the results when using the two calibration approaches, a systematic error is probable. Possible reasons for this error are discussed (e.g., the cross-sectional ratio, in the case of xenon reference measurement calibration). One main conclusion is that measurements that are performed using the reference measurements on xenon are preferred, because they have much fewer experimental factors to be taken into account.