A time-of-flight mass reflectron with controlled ion-energy spread in the packet generated by an ion source

Abstract

A new principle is proposed for eliminating the energy spread of ions in a packet generated by the ion source of a time-of-flight (TOF) mass reflectron. The ion source is treated as an element of the optic tract, in which the ion trajectories are conjugated with those in the electrostatic mirror, while the primary temporal focus near the source is absent. By properly selecting parameters of the emission-reflection system comprising a combination of the ion source and electrostatic mirror, the total time of ion flight from the source to detector can be controlled so as to be independent of the ion energy. Numerical simulations have been used to find the optimum parameters of a three-electrode electrostatic mirror possessing rotational symmetry, which simultaneously ensure the TOF control (to within third-order terms) and the spatial focusing of ions in the detector plane.