New absolute cross section measurement for the reaction H-+e to H++3e- is reported for interaction energies from threshold to 2 keV by using the animated crossed beam method. The present results confirm the disagreement between the previous results of this laboratory and the results of Peart et al. (1970, 1971).

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The first absolute cross section measurements for single and double electron impact ionization of sodium-like A?* are reponed. The animated crossed beams method has been employed in the energy range from threshold to 3000eV. The measured cross sections for single ionization are higher than the theoretical and semi-empirical predictions by about 20-50%. This discrepancy has been associated with the contribution o f the indirect ionization processes. The double ionization cross section is only 1% of the single one.

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Measured cross sections for single ionisation of Li-like N4+, O5+ and Ne7+ by electron impact are reported for energies from threshold to 2500 eV. The animated crossed beams method has been employed. In addition to direct ionisation, the 1s22s to 1s2l2l' excitation followed by autoionisation is shown to give a significant contribution to the total cross section, and its magnitude has been estimated for all three ions. Comparisons are made with other experimental results and different theoretical predictions. Cross sections for N4+ and O5+ are in a good agreement with previous results and the first result on Ne7+ ionisation is well reproduced by the Coulomb-Born calculations.