1981 年 50 巻 10 号 p. 1040-1048
A drift tube was constructed for absolute measurements of ionic transport coefficients and reaction rate coefficients of clustering in the pressure range 1.0_??_10Torr at room temperature. In order to eliminate unknown effects at a differential pumping section, the drift tube has no mass spectrometer. Some design guides to drift tube methods are presented and a simple relation between electric fielddistortion and dimensions of guard rings is derived. Details of the apparatus andsome results are reported. The systematic error and the random error of the apparatus are estimated to be ±1.0% and ±0.5%, respectively, at the measurement of mobility.