A Faraday cup is a device that measures the beam current, or how strong an ion beam is. It is very useful for ascertaining that the beam is aligned properly. There are a number of Faraday cups in our system:
LE (low energy) Faraday Cup
Located downstream of the ion optics in the ion source, and upstream of the tandem. Maximizing beam current at the LE cup should mean that the ionizer is functioning, and that the beam is aligned effectively to enter the tandem for acceleration.
HE (high energy) Faraday Cup
Located downstream of the tandem, and upstream of the high-energy ion optics. Maximizing beam current at the HE cup means that the tandem has successfully accelerated the ion beam, and that this beam may now be manipulated for into the target room to create the nuclear fusion reaction.
IM1 (Image 1) Faraday Cup
This cup was for use with the LINAC and is now defunct.
IM2 (Image 2) Faraday Cup
Located downstream of the analyzer magnet, slits, and high energy ion optics; located upstream of the target room. Maximize the beam current to this cup by adjusting the levels of the high energy optical elements.