| 摘要 |
<p>An apparatus and a method are disclosed for rapidly controling the rate of ion generation in an ion source. The ion source includes an ion chamber, filament-cathode, a mirror electrode, and a grid. The ion source is operable to generate an ion beam from the ionization of ion precursor gas present in the ion chamber bz electrions emitted from the filament. The rate of ion generation is controlled by modifying the potential of the grid relative to the filament to control the number of electrons available for ioniation between the grid and the mirror electrode. An alernative embodiment for rapidly controlling the rate of ion generation in an ion source is disclosed. In the alternative embodiment, the ion source comprises an ion chamber having mutually opposed sides and congifured to receive ion precursor gas; a filament-cathode located on one side of said ion chamber and operable to emit elctrons for the ionization of the precursor gas for the generation of the ion bean; and a mirror electrode having a potential associated therewith and located on the other side of said ion chamber. The mirror electrode is connected to a circuit to vary its potential relative to said filament so as to vary the number of the electrons available in the ion chamber for ionization.</p> |
