Absolute cross sections for single and double ionisation of Mg atoms by electron impact

In a crossed-beam experiment absolute cross sections for ionisation by electron impact are measured for the processes Mg+e to Mg + +2e and Mg+e to Mg 2+ +3e. The Mg + and Mg 2+ ions are separated by a time-of-flight method. Electron energies are varied between 30 eV and 280 eV. Cross sections at the maximum of the ionisation functions are 7.8*10 -16 cm 2 (Mg + ) and 9*10 -18 cm 2 (Mg 2+ ).