抄録
The ion mobility of He+ in He gas has been measured at 4.4 K and 85.7 K using a selected ion drift tube apparatus which has a cryogenic system. The thermal transpiration effect on pressure measurement was found to be very large and important at such a very low temperature. The pressure correction was made according to a semiempirical method proposed by Poulter et al. The reduced mobility, when plotted against effective temperature, agrees well with other experiments at high temperatures. As the effective temperature is decreased, the reduced mobility increases and reaches the Langevin limit at about 18 K, and then appears to decrease below that temperature. This may be the first evidence of what Dickinson predicted theoretically though further, more precise measurements are required.
