Fermi National Laboratory

Combination Store (Combo Platter)

The reason why the Tevatron has been producing record-breaking luminosities is because of the accelerator complex's ability to produce combination stores.

The Main Injector sends protons to the Antiproton Source's nickel target, which makes the antiprotons. The Debuncher manipulates the antiprotons and stores them in the Accumulator, but its storage capacity is limited.

The Antiproton Source alone can easily produce stores with good luminosity, but to get beyond good it needs help. So, the Antiproton Source transfers antiprotons to the Recycler. The Recycler packs the antiprotons closer together than the Accumulator can, making a denser batch of beam. An empty Accumulator can then restack even faster.

When it comes time to establish a store, the Main Injector first loads the Tevatron with protons. At present, the Main Injector takes two shots of antiprotons from the Antiproton Source and loads them into the Tevatron, two shots from the Recycler, two more from the Source, one more from the Recycler, and then the last two from the Source. However, this combination can come in any order desired. One of the benefits of this method is that while the Recycler is giving up its antiprotons, the Accumulator cools (packs tighter) its remaining particles. Another benefit is the Recycler and Antiproton Source's ability to manipulate the antiprotons in different ways.

Once the Tevatron has all the particles, it ramps them up to near the speed of light, and then begins squeezing the particles into focal points located at B0 (CDF) and D0 (D-Zero) where the particles collide.


last modified 04/1/2005   email Fermilab