The
performance of the LEBIT buncher has been checked by simulating the entire
ion manipulation process. Injected ions were subjected to the electric field
of the electrode structure calculated with the SIMION v7 software. The
damping force of the He gas was taken into account by MC-type simulations of
the scattering processes between ions and He atoms.
Realistic potentials derived from ion mobility data were used to model the interaction between the collision partners. As an example the figure below illustrates the trapping process for a 23Na ion.
The figure to the right shows the calculated transverse and axial phase-space occupied by a 2keV-energy pulse of 133Cs ions ejected from the buncher system operated at room temperature. The transverse emittance of the pulse is ~14 p mm mrad (95%-ellipse) whereas the axial phase-space is ~ 10 eV ms (80%-ellipse).
