Patent ID: 8237111

Claim:
A multi-reflecting ion optical device comprising electrostatic field generating means configured to generate electrostatic field defined by a superposition of first and second mutually independent distributions of electrostatic potential (Φ EF , Φ LS , whereby ion motion in a flight direction is decoupled from ion motion in lateral directions, orthogonal to the flight direction, said first distribution of electrostatic potential (Φ EF being effective to subject ions having the same mass-to-charge ratio to energy focusing with respect to the flight direction and said second distribution of electrostatic potential Φ LS being effective to subject ions to stability in one said lateral direction, to stability in another said lateral direction for the duration of at least a finite number of oscillations in said one lateral direction and to subject ions having the same mass-to-charge ratio to energy focusing with respect to said one lateral direction for a predetermined energy range.