Patent ID: 7351958

Claim:
An ion optics system comprising: a first ion mirror; a second ion mirror, the first ion mirror and the second ion mirror disposed on opposite sides of a first plane such that the first ion mirror has a position that is substantially mirror-symmetric about the first plane relative to the position of the second ion mirror; a third ion mirror; and a fourth ion mirror, the third ion mirror and the fourth ion mirror disposed on opposite sides of the first plane such that the third ion mirror has a position that is substantially mirror-symmetric about the first plane relative to the position of the fourth ion mirror; wherein the first ion mirror, the second ion mirror, the third ion mirror and the fourth ion mirror are arranged such that a trajectory of an ion exiting the ion optics system can be provided that intersects a surface substantially parallel to a focal surface of the ion optics system at a position that is substantially independent of ion kinetic energy.