エアロゾル両極拡散電荷中和器の荷電効率とイオン移動度の時間変化の関係

抄録

In our previous study (Sato et al., 2011), we observed that the charged fractions of ²⁴¹Am neutralizers deviated from those calculated by Wiedensohler (1988) under some conditions. Inspired by the work by Nagato and Ogawa (1998), in which they observed the mobility of positive ions decreased sharply in a time scale of tens to hundreds of milliseconds after the ions were generated by radioactive ionization of ²⁴¹Am, while the mobility of negative ions did not change in the same time scale, we developed a method to calculate positive ion mobilities from the observed deviations of charged fractions. The positive ion mobilities thus obtained were compared to and found to agree well with those by Nagato and Ogawa (1998). In this article, the above method of calculating the positive ion mobility is reviewed first, and then the method was applied to a new data set that we recently obtained. The positive ion mobilities for the new data set agreed well again with those by Nagato and Ogawa (1998). The agreement implies that the change of the charged fractions observed in our studies may be associated with changes of the mobility of positive ions in the neutralizer.