Mobilities of Ne+ and Ar+ Ions in He Gas at 82 K

Mobilities of Ne + and Ar + ions in He gas were studied at 82 K. An injected-ion drift tube mass spectrometer, the drift tube of which can be cooled with liquid nitrogen was developed for this purpose. The mobility curves obtained have a bump at intermediate E / N , and the zero-field reduced mobilities have approached to the polarization limits. The He peculiarities which have been known for long time are explained clearly by the temperature effects found in this work.