Mobilities of positive ions in some gas mixtures used in proportional and drift chambers

We have measured the mobility of positive ions in several gas mixtures frequently used in proportional and drift chambers, namely Ar-(OCH3 )2CH2, Ar-(OCH3)2CH 2-IsoC4H10, Ar-CH4, and Ar-CO 2. In all gas mixtures considered, Blanc's law of positive ion mobility has been verified, except for a very small methylal concentration in argon-isobutane-methylal. The law permits the calculation of ion mobility in any mixture of the gases considered