Confinement of Pulse-Injected External Ions in Magnetostatic and Electrostatic Ion Traps

Numerical methods are used to evaluate the confinement properties of both a Penning ion trap and a purely electrostatic ion trap for pulsed ion injection from an external source. Hereby the optimum time intervals for switching on the storage fields are obtained for singly charged ions of mass 100 u and energies up to 100 eV, as an example. For the Penning trap only axial injection along the external magnetic field is feasible. In the case of the purely electrostatic trap both axial and radial-equatorial plane incidence directions are considered. It is shown that for both storage devices practically all ions in a pulse of one microsecond duration can be trapped for properly chosen time delays and injection parameters.