Generating a Sustained Oxygen-Stable Atomic Concentration in a High-Temperature Gas Effect Investigation

Area of Science:

• Atomic physics
• Plasma science
• Spectroscopy

Background:

• Modulated laser absorption spectroscopy is vital for analyzing high-temperature environments.
• Accurate calibration requires transient atomic samples of known concentrations, which are difficult to prepare.
• Existing methods struggle with the stability and known concentration of atomic samples.

Purpose of the Study:

• To establish a reliable method for generating transient atomic samples with known concentrations.
• To utilize glow discharge plasma for continuous production of oxygen atoms.
• To enable absolute concentration calibration for laser absorption spectroscopy.

Main Methods:

• Alternating-current glow discharge was used to dissociate oxygen in airflow.
• Direct absorption spectroscopy at 777 nm determined absolute oxygen atom number densities.
• Discharge parameters were adjusted to control atom densities.

Main Results:

• Continuous generation of oxygen atoms was achieved.
• Stable concentration of excited-state oxygen atoms was maintained at (2.51 ± 0.02) × 10^8 cm^-3 for 120 minutes.
• Glow discharge plasma demonstrated remarkable stability for transient atomic concentration.

Conclusions:

• The glow discharge technique provides a stable and reliable source of oxygen atoms.
• These generated atoms can serve as standardized samples for absolute concentration calibration.
• This method overcomes challenges in preparing transient atomic samples for spectroscopy.