Quantitative analysis of trace N-2, Ar in O-2 using glow discharge optical emission spectroscopy

Abstract

A trace level of N-2 and Ar gases in O-2 ambience were quantitatively analyzed for the first time by glow discharge optical emission spectroscopy. Microplasma was generated in a compact gas cell by a metal (Au) electrode pair of 1 mm diameter and similar to 1 mm separation with the driving voltage of similar to 0.9 kV and the current of similar to 5 mA in similar to 60 Torr. 358 and 813 nm optical emission bands were used for N-2 and Ar detection, respectively. A spectroscopy fiber bundle having a circular input cross section of similar to 700 mu m in diameter and an output of 100 mu m in width and 3 mm in height was employed to promote the signal collection efficiency while preserving high spectral resolution. As a result, the detection sensitivities < 1 ppm (3 - sigma) were attained for both N-2 and Ar within 10 s. The detection accuracy was also promoted by correcting the N-2 and Ar band signal intensities using the neighboring O emission band intensities, which led to detection errors < 2% (3 - sigma) for both N-2 and Ar. Published under an exclusive license by AIP Publishing.