Principle of different containment techniques (other than ICR)

The simplest confinement device is a cylindrical capacitor with a thin conductive wire as the inner frame. The ions created inside the device execute complex trajectories in the logarithmic potential, as described by Hooverman and Knight. In principle, the duration of confinement is infinite for all ions having a non-zero tangential velocity at the time of their creation. However, collisions with the residual gas cause the ions to neutralize on the central electrode, which necessarily has a finite diameter. Ions can be ejected radially by the application of a destabilizing voltage between the armatures, and a small fraction of these can be focused on the entrance slit of a mass analyzer or directly on a detector. Under certain shape conditions imposed on the electrodes,...