Ion trajectories in the field-ion microscope

The trajectories of the imaging ions in the field-ion microscope have been determined for hyperboloidal and paraboloidal emitter shapes. The shape of the trajectories has been shown to be independent of the potential difference between the emitter and the microscope screen and the charge-to-mass ratio of the ion. It has also been found to vary little with tip-to-screen distance and nose curvature. The stereographic projection is found to be in good agreement with the calculated results.