Resolution and spectral‐line shapes in the reflecting time‐of‐flight mass spectrometer with orthogonally injected ions

Abstract

Abstract Principal factors limiting the resolution of time‐of‐flight (TOF) mass spectrometers based on ‘orthogonal’ ion beam acceleration have been studied theoretically. It has been found that the construction of the orthogonal acceleration TOF mass analyzer enables, in some cases, the simultaneous compensation of both ion spatial and initial velocity distributions by appropriate selection of ion‐mirror potentials. This analytical result has been proved by numerical simulation of spectral line shapes. The influence of elementary cell dimensions of grids on the mass resolution has been investigated by the numerical integration of a large number of ion trajectories. The grids consisting of a set of parallel and equally spaced wires have been treated. Analytical approximations of the electrical field potential of the grids have been used. It has been found that optimization of TOF mass analyzers should include the treatment of ion scattering by grids.