Electron mobility in liquid and supercritical helium measured using corona discharges: a new semi-empirical model for cavity formation.
Electron mobilities in supercritical and liquid helium were investigated as a function of the density. The mobilities were derived from I(V) curves measured in a high-pressure cryogenic cell using a corona discharge in point-plane electrode geometry for charge generation. The presented data spans a wide pressure and temperature range due to the versatility of our experimental set-up. Where data from previous investigations is available for comparison, very good agreement is found. We present a semi-empirical model to calculate electron mobilities both in the liquid and supercritical phase. This model requires the electron-helium scattering length and thermodynamic state equations as the only input and circumvents any need to consider surface tension. Our semi-empirical model reproduces experimental data very well, in particular towards lower densities where transitions from localised to delocalised electron states were observed.
G2ELab-CNRS, 25 rue des Martyrs, 38042 Grenoble, France. frederic.aitken@grenoble.cnrs.fr
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Aitken
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Bonifaci
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von Haeften