On the measurement of electron impact ionisation cross-sections for highlycharged ions using an electron beam ion trap (EBIT)

Experiments in which the time evolution of the charge distribution of Argon ions in the Tokyo EBIT was measured have been carried out. These measureme nts involved extracting the ions from the trap after a controlled confineme nt time and determining the charge distribution of these ions. By repeating the procedure at various confinement times the onsets for ions of particul ar charge states were determined at a series of electron beam energies. Thi s sort of data should permit electron impact ionisation cross-sections to b e determined as well as providing interesting information relating to EBIT physics.