Quadruple focusing time of flight mass spectrometer

Claim 1

A quadruple focusing time of flight mass spectrometer comprised of means including an entrance plane and an exit plane defining an ion flight path in which parcels of ions divide into partial parcels of equal effective mass, a pulsed ion source which emits a parcel of accelerated ions across said entrance plane into the flight path, and means for detecting the partial parcels of ions beyond said exit plane and recording their elapsed time of flight between said entrance and exit planes, said flight path defining means including a deflection zone comprised of first, second, third, and fourth separate focusing means for each in sequence guiding the ions through a deflection arc with limited divergence from a central reference plane, characterized in that said second and third focusing means share a common central reference plane which is perpendicular to central reference planes of said first and fourth focusing means and said first and second focusing means define a first segment of the ion flight path in said deflection zone which is a mirror image of a second segment of the ion flight path formed by said third and fourth focusing means, so that ions enter and exit from said deflection zone traveling in opposite directions.