Fermi National Laboratory

Accelerator Update

Monday November 10 through Wednesday November 12
All shifts began in shutdown.

On Monday morning a controls technician had a generator installed at Tevatron (TeV) sectors A1, A2, and A3 to get water readbacks during the power outage during the high voltage cable replacement. Operators monitored the level of water in the sump pits in A1, A2, and A3 throughout the day and night and manually pumped the water out when it got too high. A Linac quadrupole power supply (QPS106) caused a lot of problems throughout the evening shift.

On Tuesday, experts tested the Antiproton Source (Pbar) power supplies. Booster experts conducted studies. The TeV LCW system was not run, but it was pressurized from CUB. By the end of day shift, operators had begun turning on Pbar. The Duty Electrician had power restored to TeV sectors A1, A2, and A3 by 4:30 PM. Cryo techs began cooling the cryo system as soon as power was restored.

On Wednesday Booster studies continued until 3 AM. Techs completed their safety system tests of the Main Injector, D-zero, Booster, and TeV by 6 AM.

Future Plans
Operations hopes to send beam to Pbar tonight and beam to the TeV tomorrow night. Booster and MI experts will working on tuning their beamlines.

The Fermi Accelerator Complex
Here is a very brief primer about the Fermi accelerators.

The Preaccelerator (Preacc)
This is the source of all beam at Fermilab. It is presently configured to produce the negatively charged hydrogen ion that the Linac accelerates. We have two source so that we can keep one operating at all times. The Preacc accelerates beam to a potential of -750 KeV.

The Linac takes the Preacc beam and accelerates it 400 MeV. It does this by RF drift tubes (older technology that uses power amplifiers) and side-coupled cavities (newer technology that uses Klystrons to generate the RF) arranged in a straight line.

The Booster first strips off the extra electrons from the hydrogen particle and then accelerates them to 8 GeV. The Booster is a circular accelerator with a 75-meter radius that contains magnets and 18 RF cavities. The Booster sends beam to the Main Injector and to the MiniBooNE experiment.

Main Injector (MI)
The Main Injector is a circular accelerator that is a little more than half the circumference of the Tevatron. It contains various magnets and 18 RF cavities, which accelerates beam to either 120 GeV for Antiproton Source and Switchyard or 150 GeV for the Tevatron. It accepts beam from the Booster and the Antiproton Source and sends beam to the Tevatron, the Recycler, the Antiproton Source, and to the NuMI experiment.

Tevatron (TeV)
The Tevatron has a circumference of about four miles that is considered a circular synchrotron, which contains eight RF cavities. It accepts both protons and antiprotons from the main injector and accelerates both to 980 GeV. Presently, the Tevatron is the highest energy accelerator in the world. It uses cryogenically cooled magnets (made of a niobium titanium alloy), cooled to about 4 degrees Celsius above absolute zero that controls the particle beams. The Tevatron houses two collider experiments where the beams get focused to cause proton antiproton collisions. The Tevatron accepts and sends beam to and from the Main Injector.

Antiproton Source (Pbar)
The Antiproton Source is made up of three distinctive parts: the Target, the Debuncher, and the Accumulator. The Antiproton Source is not an accelerator.

The Main Injector sends protons to a target that produces many particles, one of which is an antiproton. All other particles are swept way and the antiprotons get sent to the Debuncher.

The Debuncher is a triangular shaped synchrotron that captures the antiprotons and cools them, which makes the beam more manageable. The Debuncher maintains the beam at an energy of 8 GeV and sends it to the Accumulator.

The Accumulator is also a synchrotron housed in the same triangular shaped tunnel as the Debuncher. It is primarily a storage ring for antiprotons.

The Antiproton Source accepts beam from and sends beam to the Main Injector.

Recycler (RR)
The Recycler is a dedicated antiproton storage ring located in the Main Injector. It is built primarily of permanent magnets. The Recycler's purpose is to accept antiprotons from the Antiproton Source and to shoot antiprotons to the Tevatron, both done through the Main Injector. The Recycler does not accelerate particles.

Accelerator Update Archive

More Information
For Tevatron luminosity charts and the current status of Fermilab's accelerators and detectors (live!), please go to Fermilab Now

Comments and Suggestions
What do you think about the Accelerator Updates? Please send comments and suggestions to: accelupdates@fnal.gov.

last modified 11/12/2003   email Fermilab