Accelerator Update

About the Fermilab Accelerators

Accelerator Magnets
Whether superconducting or conventional, magnets work the same way, they keep control of Fermilab's particle beam. Perhaps you've read here that technicians were working on correction or focusing elements in some accelerator, or dipoles and quadrupoles in another, and wondered what they were? They are the same two things, actually, just different names. A magnet controls the particle beam's position due to the field of force generated by the current running through its conductor. Here is a list magnet names and their basic functions:

Dipole
These magnets are also called "Bend," "Trim," or "Correction" magnets. This style of magnet has one North pole and one South pole. It generally bends the beam in either a horizontal or vertical direction.

Quadrupole
These magnets are also called "Focusing," "Defocusing," or "Low Beta" magnets. This style of magnet has two North poles and two South poles. The best explanation of their function is an optical one. Picture a magnifying glass; it has two convex surfaces that gather divergent rays of light together and focuses them to a spot - that's a focusing quadrupole. A defocusing lens does just the opposite; it spreads rays of light apart - that's a defocusing quadrupole. Low Beta Magnets are what the Tevatron uses to collide protons and antiprotons at the CDF and D0 experiments.

Lambertson
A Lambertson magnet is a special dipole that contains two areas for beam. One area has a magnetic field and will bend the beam. The other area is shielded from the field and the beam simply passes through it. This style of magnet is used to either join two beams together or to separate them apart. An example of joining beams would be blending the Main Injector beam into the circulating Tevatron beam.

Analyzing
Usually, this is an extremely large dipole magnet with a very precise magnetic field. Along with other equipment, it is used to measure particle spin and momentum.