ON THE CORRELATION BETWEEN ELECTRON-MOBILITY, FREE-ION YIELD, AND ELECTRON THERMALIZATION DISTANCE IN NONPOLAR DIELECTRIC LIQUIDS

The correlation between the thermal electron mobility, mu(e), the radiation-induced free-ion yield G(fi) at zero applied electric field, and the most probable thermalization distance b of secondary electrons, is examined for 52 different pure nonpolar dielectric liquids for which data have been reported in the literature. It is shown that, in liquids for which mu(e) > 10(-1) cm2 V-1 s-1, the variation of G(fi) with mu(e) is well represented by a relation of the type G(fi) is-proportional-to (mu(e))n, where n almost-equal-to 0.31. The connection between G(fi) and mu(e) can be described through the product epsilon(s)b, where epsilon(s) is the static dielectric constant of the intervening liquid. In particular, 1/epsilon(s)b is shown to correlate with both mu(e) and G(fi). Analysis of these correlations allows us to estimate an upper limit of mu(e) that can be attained in a room-temperature dielectric liquid, information of utmost importance from the point of view of application to liquid ionization detectors.