Abstract
We analyzed the electron arrival time signal measured in pure oxygen and in dilute oxygen-argon mixtures by using a double shutter electron drift tube with variable drift distance and derived the density normalized attachment coefficient for respective gases. The present attachment coefficient detennined for pure oxygen agreed well with previously reported values and we confirmed that the present apparatus was useful in determining electron attachment coefficient even if there were no ionization, when there will be no steady state current growth and, hence, the steady state Townsend (SST) method can not be applied in principle. The measured attachment coefficients in the mixtures agreed very well with the calculation using our latest cross section set for the oxygen molecule and that will be a confirmation for the validity of the cross section set.
