Mobility of ions in solid helium

Abstract

We have studied the mobilities of positive and negative ions in solid helium 3 and 4, by measuring directly the time of flight in an electric field. These mobilities vary exponentially with inverse temperature, leading to an activation energy. In addition, we have detected trapping of negative ions. Finally, in hexagonal helium 3, we have observed a discontinuity in the temperature variation of the mobility of positive ions