Experimental measurement of the mobility of ions originated in ethane in their parent gas

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 (C2H6) 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 cm2V−1s−1 and 1.47 cm2V−1s−1, which are likely to belong to a 3-carbon ions group which includes C3H5+, C3H7+, C3H8+ and C3H9+ and to a 4-carbon ions group which includes C4H9+ and C4H10+ ions. For typical reduced electric fields used in gaseous detectors (E/N > 15 Td), the mobilities were 15% smaller than the Langevin limit [1].