radial electrostatic field analyser

in mass spectrometry
An arrangement of two conducting sheets forming a capacitor and giving a radial electrostatic field which is used to deflect and focus ion beams of different energies. The capacitor may be cylindrical, spherical, or toroidal.
Orange Book, 2nd ed., p. 201 (https://media.iupac.org/publications/analytical_compendium/)