Patent ID: 7034288

Claim:
A time-of-flight mass spectrometer comprising: an electron impact ion source fitted with source magnets for enhancing the efficiency at which sample gas is ionized; an ion reservoir for gathering ions produced in said ion source, wherein said ions travel from said ion source to said ion reservoir along an axis; an ion repeller plate and grids disposed on opposite sides of the ion reservoir to impulsively accelerate the ions out of the reservoir; a time-of-flight mass analyzer region for mass separating the ions extracted from the ion reservoir via the grids; an ion detector for detecting the mass separated ions; first deflection means mounted between the ion source and the ion reservoir for deflecting the ions in a direction generally perpendicular to said axis and in the same direction as the direction of deflection that the ions traveling from the ion source to the ion reservoir undergo from a magnetic field produced by the source magnets; and cutoff means located between the first deflection means and the ions reservoir to cut off the deflected ions.