Gas temperature measurements in a pulsed, low-pressure inductively coupled plasma in oxygen

Abstract

Optical emission spectroscopy (OES) of the magnetic dipole allowed O2(b1Σg +) to O2(X3Σg −) transition was investigated as a non-intrusive gas temperature diagnostic for E-mode and H-mode inductively coupled plasmas (ICP) in oxygen. It was compared to tunable diode laser absorption spectroscopy using Ar admixtures, and OES of the nitrogen Second Positive System with nitrogen admixtures. O2 OES provided accurate results for the E-mode ICP, 400–600 K for powers of 100–300 W, but in H-mode the method was unsuitable probably because of excitation of O2(b1Σg +) by metastable atomic oxygen. Rotational temperatures were measured, using N2 OES with N2 admixtures, for pulsed operation of the ICP with a 30 ms pulse duration and 15% duty cycle. It took 1–3 ms before the steady-state rotational temperatures were achieved. In addition, a small variation of matching network settings affects the plasma ignition delay time by several ms.

Ozone production by an He+O2 radio-frequency atmospheric pressure plasma jet driven by tailored voltage waveforms

“…An example of a measured N 2 (C-B) (v = 0 → 0) spectrum and simulated fit are shown in figure 6. Measured spectra are fitted with a code used in previous studies [64,[77][78][79][80][81]. The simulation is modelled according to Herzberg [82], with rotational constants from Roux et al [83] and line strengths calculated from Kovács [84] and Schadee [85].…”