The following is adapted from an article titled Producing
"The Beam" in the October 6, 1995 FermiNews, written
by Donald Sena of the Office of Public Affairs.
Producing "The Beam" - From Shut Down to Start Up
There would be no discoveries at all without the critical component
at Fermilab that comes from the Accelerator team - the beam. The
beam, a stream of subatomic particles forced into dramatic collisions,
is the main tool used to get to the heart of the universe's matter.
"In the case of the top quark . . .not many events can occur
even in a particle accelerator. The ability to see an occasional
event is (fairly) rare, and so you need lots and lots of beam
and you need the beam to be there continuously. Without it . .
.the physics would be at a very very slow rate; it would take
literally years to . . .gather the data, and in some cases (experiments)
couldn't be done." said Bob Mau, department head, Accelerator
Division Operations. "Without the particle beam there are
no events and no apparatus will detect anything. It's really that
For experiments to begin a date is set and numerous tasks are
set in motion that eventually lead to collisions at the detectors.
Soon after the date is set, workers turn on the water system and
purify the water. Many of the magnets and power supplies are water-cooled.
The water must be as pure as possible. Conductive water, like
the kind in homes, can short out these magnets.
Accelerator staff then secure and power up the Preaccelerator,
Linac and Booster ring. To secure beam enclosures, operators walk
the areas looking for workers. Safety personnel hide dummies in
the enclosures to ensure a thorough search; if the team misses
a dummy, they search the entire area again and possibly receive
more training. Workers have missed only three dummies in 24 years.
To "power up" the various systems, workers make sure
all components, such as magnets, have been installed and work
Operators and physicists then begin to inject beam into the Preaccelerator,
Linac and Booster rings. Soon after, they secure and power up
the Main Ring and Tevatron with timing so precise that the Main
Ring and Tevatron will be ready when the beam has accelerated
to that point. Beam will eventually accelerate through the Preaccelerator,
Linac Booster, Main Ring and Tevatron before reaching the detectors.
All of these steps are critical to providing enough continuous
beam for the end results of the experiments. Watch for future
articles on the next stage, the Detectors.
Operators in the Main Control Room use computers to monitor
and control the various stages of the accelerator.