The Electron Gun generates an intense beam of electrons which travels along the axis of the EBIT and strips electrons from atoms which lie in its path, thereby forming highly charged ions. In the NIST EBIT, the electron gun is mounted on a small high-voltage platform so that in the future our EBIT can be made to operate at even higher electron beam energies.
The electron gun is of a Pierce design and contains a cathode with a heated tungsten element infused with barium oxide to reduce the work function. The cathode is a partial sphere with .3 cm diameter. Above the cathode is a focus electrode and anode. The gun is mounted beneath an iron plate which helps shape the local field lines. The gun chamber is at room temperature.