Time-of-flight measurements of electron transport parameters in CO2-H2-He gas mixtures

The drift velocity and longitudinal diffusion coefficient have been obtained for electrons in six CO2-N2-He gas mixtures with gas ratios 2:1:3, 1:1:8,1:2:3, 1:7:30, 4:1:12 and 1:1:3. A time-of-flight technique was employed to obtain accurate measurements in the range of 0.71 < E/N < 565 Td (E/N is, the ratio of electric field to gas number density and 1 Td = 10¿¿21 Vm2). A comparison is made with the theorectical calculations of Lowke et al, the experimental values show good agreement at low E/N, but at high E/N the experimental values are larger than the theoretical values.