Research on the electron attachment of oxygen using a Frisch-grid ionization chamber

The electron attachment is studied using a Frisch-grid ionization chamber (GIC) with different number densities of O-2 in the working gas and different reduced electric fields. The influence of the electron attachment on the cathode-anode two-dimensional amplitude spectrum of the GIC is measured and evaluated. The method of measuring the attachment probability per unit time using the GIC is established. The quantitative and systematic relationships between the attachment probability per unit time and the number density of O-2 and the reduced electric field are obtained from experiments, where the number densities of O-2 are from 0 to 2.29 x 10(17) cm(-3) and the reduced electric fields are from 22 to 577 V/cm/bar. The three-body attachment coefficients of O-2 at different mean electron energies (< 1 eV) are measured, which are consistent with those from previous works. For the first time, the three-body attachment coefficients of CO2 at different mean electron energies (<1 eV) are measured. It is found that the three-body attachment coefficients of O-2 and CO2 are nearly the same at the same mean electron energy.