Simple geometry gridless ion mirror.

A gridless variation of the cylindrical ion mirror has been designed to create an electric field that is nonlinear in the axial direction and nearly homogeneous in the radial direction. The designs may include one or two chambers that consist of truncated cones. This new design concept yields ion mirrors with improved energy focusing over conventional single-field and multiple-field mirrors. Conventionally, ion mirrors with nonlinear field gradient use multiple diaphragm electrodes to which distinct voltages are applied. In this work, optimized nonlinear field distributions are achieved through shaping only two or three electrodes and applying only one or two voltages on the electrodes. The designs presented here offer high resolving power and low ion dispersion. SIMION simulations of performance from the ion source to the detector demonstrate resolving powers of 11,000 and 1,750 for ions with kinetic energy variations of 7.5% and 23.6%, respectively.