The transport coefficients for Li+ ions in some moleculars gases have been measured over a wide range of E/N with a conventional drift tube at temperatures close to 300 K. The zero-field reduced mobilities are found to be 3.91±0.11, 4.44±0.12, 3.64±0.10, 2.46±0.07, and 3.44±0.10 cm2/V s in N2, O2, CO, CO2, and CH4 gas, respectively, and these values except in O2 gas significantly deviate from the Langevin limit. In N2, CO, and CO2 gas, the resulting mobility curves show clear minima at intermediate E/N, but the depressions in O2 and CH4 gas are slight. The drop of the zero-field values in N2, CO, and CO2 gas is explained in terms of an effective ion–quadrupole interaction which provides the r−6 attractive behavior. From the mobility calculations with using n−4–6(γ) potential, it is suggested that the depression of the mobility curve is developed by the addition of a sufficient r−6 term and is partly attributed to inelastic collisions as expected even at intermediate E/N. The experimental diffusion data are compared with the values derived from the generalized Einstein relation. For all systems, the agreement is quite good at intermediate E/N, but there are large discrepancies at other E/N. The sources of the deviation are considered to be clustering reactions and inelastic collisions at low and high field, respectively.
Two-dimensional measurement of radiation produced by natural irradiation of granitic rocks was performed by the use of an imaging plate, which is a storage film coated with photostimulated phosphor (BaFBr:Eu 2+ ). Radiation images of small volume specimens, such as thin sections were obtained with the imaging plate. Irradiation images of granitic rocks are inhomogeneous and the intensity of photostimulated luminescence per unit area, which is principally converted into the integrated dose, increases with the increasing potassium content in the rocks. The results of the present study indicate that the disintegration of 40 K is the dominant radiation source of granitic rocks. The imaging plate is a new research tool for the evaluation of the natural radioactive properties of geological materials and is applicable as a semi-quantitative two-dimensional dosimeter for natural radioactivity.
The measurements of mobility values for alkali ions in rare gases at room temperature over a wide range of E/N were completed for all 25 combinations. The experimental mobility curves were compared with a generalized mobility curve calculated from a model potential consisting of an inverse 8th power repulsive term and 6th and 4th power attractive terms, which took into account the core size, and potential well depths being determined for all the ion–gas combinations except for the cases of Rb+–He and Cs+–He from the relation between the observed maximum mobility and the ion energy. Experimental generalized mobility curves for alkali ions in rare gases were obtained using these well depths. It was found that all the experimental mobility curves were unified into a single curve using the model potential including the core size. The rate coefficients were measured for backward clustering reaction: Li+Ar–Ar, Li+Kr–Kr, and Li+Xe–Xe, using a drift tube. It was found that the activation energy is roughly half the well depth, comparing the well depths 0.550 eV for Li+–Ar, 0.710 eV for Li+–Kr, and 0.901 eV for Li+–Xe, with the activation energies obtained by Arrhenius plot for the backward reactions 0.34 eV for Li+Ar, 0.45 eV for Li+Kr, and 0.49 eV for Li+Xe.
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