FRIB Operators

Somewhat similar to dipoles, Quadrupoles also produce constant magnetic fields that the beam passes through. However, these devices have two sets of electromagnets instead of one, hence a total of four magnets producing a field. The fields produced are stronger towards the outer edges, while the in the center become weaker, and eventually leave the center spot with no magnetic field.

In the beamline, these quadrupoles are used to focus the beam as it travels. However, quads only focus in one plane of direction at a time. Due to this, it is typical to find a series of quads together, rather than separate, that way one quad can focus in the x direction, the next in the y, next in the x again, and so on.

Quadrupoles are located throughout the beamlines of FRIB, ReA, and the K500. They are usually found in groups of two or three, called doublets and triplets respectively.

• Shane: I'd clarify that firstly a “set” of magnets is two that have flipped polarities, and that the positioning changes where like polarities are across from each other