Design and Test of a Lens and Reflector System of an Electrostatic Ion Trap for Molecular Physics

An electrostatic ion trap was designed for the study of vibrational states of molecular ions. The trap consists of two einzel lenses and two parallel-plate reflectors. An optical model analogous to this trap predicts that a range of focal lengths of lenses exists where ions can be stored irrespective of the reflector's focal length. Beam tests with 1.2-keV ion beams showed that ions can be stored in this range. That storage time is 0.1 s for an Ar+ beam at a vacuum pressure of 2×10-8 Torr.