Measurement of Electron Temperature and Number Density and Their Effects on Reactive Species Formation in a DC Underwater Capillary Discharge

Abstract

The scope of this work is to determine and compare the effect of electron temperature (T e ) and number density (N e ) on the yield rate and concentration of reactive chemical species (• OH, H 2 O 2 and O 3 ) in an argon, air and oxygen injected negative DC (0-4 kV) capillary discharge with water flow(0.1 L/min). The discharge was created between tungsten pin-to pin electrodes (Φ = 0.5 mm) separated by a variable distance (1-2 mm) in a quartz capillary tube (2 mm inner diameter, 4 mm outer diameter), with various gas injection rates (100-800 sccm). Optical emission spectroscopy (OES) of the hydrogen Balmer lines was carried out to investigate the line shapes and intensities as functions of the discharge parameters such as the type of gas, gas injection rate and inter electrode gap distances. The intensity ratio method was used to calculate T e and Stark broadening of Balmer β lines was adopted to determine N e . The effects of T e and N e on the reactive chemical species formation were evaluated and presented. The enhancement in yield rate of reactive chemical species was revealed at the higher electron temperature, higher gas injection rates, higher discharge power and larger inter-electrode gap. The discharge with oxygen injection was the most effective one for increasing the reactive chemical species concentration. The formation of reactive chemical species was shown more directly related to T e than N e in a flowing water gas injected negative DC capillary discharge.

Trace metal analysis of element on material surface using pulse CO2 laser-induced breakdown spectroscopy applying vaporization technique

“…Prior to semi-quantitative analysis of Cr trace element deposited on Si surface, the characteristics of plasma emission such as temperature and electron density were calculated. By considering that the population densities of the higher energy levels of two emission lines are in LTE condition, the calculation of electron temperature (Te) can be derived by the intensity ratio method [ 44 ]. In this study, the Te was obtained from the hydrogen lines of Balmer region using Eq.…”