An angle-resolved translational energy spectrometer for investigating low-energy, highly charged ion–atom (molecule) collisions

Abstract

An experimental apparatus for investigating low-collision energy gas-phase reactions of highly charged ions with atoms and molecules by angle-resolved translational energy spectroscopy is described. The basic function of the apparatus is to slow down highly charged ions extracted at 2–3 kV from the Cornell superconducting solenoid, cryogenic electron beam ion source (CEBIS) to energies below 100 qeV. The slowing down and monochromatization of the beam is done by an ion optical system that consists of two 180° hemispherical electrostatic analyzers with a tuneable deceleration lens located between them. The low-energy beam available for experiments has an angular spread of 0.5° and an energy spread of 0.4 qeV. The ion optical system is mounted on a 508 mm by 576 mm electrically isolated platform inside a large vacuum chamber, and the modular nature of the apparatus allows for quick and easy rearrangement of the ion optical elements for different experiments. A brief overview of in-plane scattering kinematics is given.