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In this paper we present the experimental results for the mobility of ions in argoncarbon dioxide gaseous mixtures (Ar-CO 2 ) for pressures ranging from 6 to 10 Torr and for reduced electric fields in the 10 Td to 25 Td range, at room temperature.The time-of-arrival spectra of the several mixture ratios studied revealed that the relative abundance of the ions and their mobilities depend on the mixture ratio. For Ar concentrations below 80% only one peak was observed in the spectra which was attributed to CO + 2 , while for Ar concentrations above 80% a second peak appears at the left side of the main peak, which may be due to impurities, probably H 2 O + . In this work, the time-of-arrival spectra from which reduced mobilities were obtained for Ar concentrations of 20% (K 0 = 1.141 ± 0.004 cm 2 V −1 s −1 ), 50% (K 0 = 1.385 ± 0.009 cm 2 V −1 s −1 ), 85% (K 0 = 1.690 ± 0.022 cm 2 V −1 s −1 ) and 95% (K 0 = 1.954 ± 0.043 cm 2 V −1 s −1 ) are displayed as well as other reduced mobilities values obtained similarly. The ion mobility study was performed at reduced electric field values typically used in gaseous detectors.

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A recent experimental technique was used for measuring the mobility of positive ions originated from ethane in their parent gas.In this particular experiment, measurements were made in pure ethane (C 2 H 6 ) for pressures ranging from 6 to 10 Torr and for reduced electric fields varying from 6 to 42 Td. The time of arrival spectra revealed two peaks and their reduced mobilities were determined. Extrapolation to zero field led to the values of 1.58 cm 2 V −1 s −1 and 1.47 cm 2 V −1 s −1 , which are likely to belong to a 3-carbon ions group which includes C 3 H + 5 , C 3 H + 7 , C 3 H + 8 and C 3 H + 9 and to a 4-carbon ions group which includes C 4 H + 9 and C 4 H + 10 ions. For typical reduced electric fields used in gaseous detectors (E/N > 15 Td), the mobilities were 15% smaller than the Langevin limit [1].