Measurements on the mobility of Ions and Ionic clusters in gases using24mNa+ as 20 msec tracer
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Mobilities of sodium ions and their clusters in gases have been measured by gamma-ray spectrometry using the 20 ms isomeric state of24Na as tracer. This isomer is obtained through the decay of24Ne which was produced by bombarding22Ne with a 7 MeV triton beam.
This new technique of measurement allows to determine the mobility of sodium ions in non-reacting gases of a pressure higher than 1 mbar. The measured mobility of24Na+ was determined to be 3.2 cm2/Vs in pure neon gas at 1000 mbar.
Measurements of the mobility of sodium ions in a diffusion cloud chamber showed a rapid decrease in the mobility in the region of supersaturation due to the growth of large clusters.
The usable pressure range from 1 mbar to high pressures in the range of some hundred bars is interesting because most other methods for cluster studies don't work at such high pressures. This method enables us to measure the mobility change towards the condensation point and eventually towards the critical point.
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- 1.Detailed information about the experiments see B. Abmayr, "Messung der Beweglichkeit von Ionenclustern unter Benutzung des 20 ms-Isomers24mNa als Tracer", Diplomarbeit at the Technical University Munich, Department of Physics, January 1989.Google Scholar
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