A gated-time-of-flight top-hat electrostatic analyzer for low energy ion measurements

When incorporated into a top-hat electrostatic analyzer, gate electrode enables the separation of ions by their mass-per-charge with modest mass resolution (M/∆M ∼ 10). Gated-time-of-flight (TOF) instruments avoid energy straggling and angular scattering effects prevalent in foil-based detection systems, providing more pristine measurements three-dimensional distribution functions incident ions. Gated-TOF implementations are ideal for measuring properties low-energy (i.e., <100 eV) thermal various space environments. We present an instrument prototype capable separating H+, He+, O+, O2+ Earth’s ionosphere demonstrate that addition to species determination, precise operation provides electronically adjustable geometric factor can extend single instrument’s dynamic range several orders magnitude.