Positive-ion drift velocities and Townsend primary ionisation coefficients in ethane

Abstract

Positive-ion drift velocities have been measured in ethane gas, using the pulsed Townsend-discharge technique, over the range 40<or=E/p<or=1400 V cm-1 Torr-1. For 40<or=E/p<or=825 V cm-1 Torr-1 positive-ion drift velocities were determined by the balanced-pulse technique, and in the range 490<or approximately=E/p<or=1400 V cm-1 Torr-1 by the positive-ion successor interval method. The experimental ion drift velocity was found to exhibit a linear dependence on E/p at low E/p changing to a square-root dependence at high E/p. Townsend primary ionisation coefficients have also been determined from balanced pulse measurements over the range 40<or=e/p<or=825 V cm-1 Torr-1. Experimental values of alpha /p are in moderate agreement with Townsend conductivity determinations, being lower at low E/p and higher at high E/p. In the range 100<or=E/p<or approximately=250 V cm-1 Torr-1 agreement is good. The effect of space-charge field distortion on the alpha coefficient, and hence the balanced pulse, is discussed. It is found that space-charge field distortion can produce different effects on the alpha coefficient in the pulsed and steady-state Townsend discharges.

Study of electron transport in hydrocarbon gases

“…6 for C 6 H 6 and C 6 H 5 CH 3 , and compared with other previously reported data. [13][14][15][16] As in Fig. 4, although there exists a slight difference between our results and other investigations for each gas, the ionization coefficient in C 2 H 6 is larger than those for the other two molecules over the E/N range in this study.…”

Cation mobilities in C1–C4 hydrocarbon gases at densities up to the critical

“…or 160 Td. This is consistent with the observed threshold at 120 Td (20). The threshold predicted from the speed of sound, 3 11 m/s, would be 100 Td.…”

“…The previously reported low field mobilities correspond to pn (loL9 molecules/cm V s) values of 6.9 (19), 6.0 (21a), and 5.9 (21b) in methane, compared to the present 6.1, 2.5 (20) in ethane compared to the present 3.1, and 1.6 (21a) in isobutane compared to the present 1. later). The gas densities used in ref.…”

“…Previous measurements indicated that the mobility was independent of field strength below about 600 Td in methane (19) and below about 130 Td in ethane (20) at 293 K and n < loi9 molecules/cm3.…”

Electron swarm parameters in C$_2$H$_2$, C$_2$H$_4$ and C$_2$H$_6$: measurements and kinetic calculations

“…At this temperature only around 85 % of the acetylene molecules are in the ground state and the vibrational population in excited states of modes v 4 and v 5 is significant. [26,29], Watts and Heylen [28], Kersten [25] and Hasegawa and Date [13]. Modelling results: BE SST, MC and BE 'Present experiment' corresponds to the uncorrected data.…”