Eliminating unwanted electrons in EBIS devices.

In electron beam ion sources, step-wise ionization to high charge states is accomplished by magnetically confined electron beam. Electron space charge and high voltage electrodes confine the ions. The relativistic heavy ion collider (RHIC) ion source Debye length meets requirements for instabilities with free source of energy to grow. Electrons stripped from ions provide energy for a variety of microinstabilities to grow. Possible solution is to remove these electrons from the trap to a drift tube biased to higher voltage than the other tubes between the gate and the collector. If needed, a split drift tube for bleeding these electrons to ground is added.