Measurements of population densities of metastable and resonant levels of argon using laser induced fluorescence

Journal Article · Wed Jan 14 04:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4905611· OSTI ID:22412814

Nikolić, M.; Newton, J.; Sukenik, C. I.; Vušković, L.; Popović, S. ^[1]

---

1. Center for Accelerator Science, Department of Physics, Old Dominion University, Norfolk, Virginia 23529 (United States)

We present a new approach to measure population densities of Ar I metastable and resonant excited states in low temperature Ar plasmas at pressures higher than 1 Torr. This approach combines the time resolved laser induced fluorescence technique with the kinetic model of Ar. The kinetic model of Ar is based on calculating the population rates of metastable and resonant levels by including contributions from the processes that affect population densities of Ar I excited states. In particular, we included collisional quenching processes between atoms in the ground state and excited states, since we are investigating plasma at higher pressures. We also determined time resolved population densities of Ar I 2 p excited states by employing optical emission spectroscopy technique. Time resolved Ar I excited state populations are presented for the case of the post-discharge of the supersonic flowing microwave discharge at pressures of 1.7 and 2.3 Torr. The experimental set-up consists of a pulsed tunable dye laser operating in the near infrared region and a cylindrical resonance cavity operating in TE{sub 111} mode at 2.45 GHz. Results show that time resolved population densities of Ar I metastable and resonant states oscillate with twice the frequency of the discharge.

• OSTI ID: 22412814
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 2 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARGON
ATOMS
CAVITY RESONATORS
DYE LASERS
EMISSION SPECTROSCOPY
EXCITED STATES
FLUORESCENCE
GHZ RANGE
GROUND STATES
HIGH-FREQUENCY DISCHARGES
METASTABLE STATES
PLASMA
PLASMA PRESSURE
POPULATION DENSITY
SUPERSONIC FLOW
TIME RESOLUTION