LHC Reawakens, Sending Proton Beams Running at the Speed of Light

Recovery: Repairwork in an above-ground warehouse on the
French-Swiss border Cern's damaged magnets underwent repairs
at a nearby above-ground site. This man is working on the end
of a dipole magnet, which contains six conductors, each of
which carried 8,000 amps but were capable of conducting up to
13,000. In superconducting magnets like this one, the
internal materials are kept at some of the lowest
temperatures imaginable, decreasing resistance and allowing
them to generate electricity with virtually no loss of heat.
Courtesy Cern

Over the weekend, Cern ran particle beams through the Large
Hadron Collider for the first time since it was shut down
last September. After a helium leak caused magnets to
overheat, operations at the LHC were suspended for cleanup
and repairs. After tests on October 23 and 25, scientists
hope to have the LHC running again in full by November.

The LHC ring -- which measures 17 miles all around -- is
divided into eight sectors, two of which were tested this
weekend. Scientists introduced proton and lead ion beams
clockwise and counterclockwise through the 2.2-mile-long
sectors. Cern reported that results showed "a perfect
functioning of the machine," in preparation for a fully
circulating beam next month.

Superconducting magnets in the LHC function at a temperature
of 2 Kelvin -- that's two degrees above absolute zero.
Maintaining this kind of cold requires the use of superfluid
helium, which in turn allows the electrical current to pass
through without encountering any resistance, Cern's Christine
Darve told PopSci.com. By sending the intense proton beams
through what she calls a "moon vacuum," scientists are able
to reap 100 times more energy than through a normal magnet.

By 2011, scientists hope to accelerate the proton beams up to
3.5 trillion electron volts, but this weekend they started
out with just 450 billion. Collisions of the beams as they
travel at near lightspeed may yield new particles, which
scientists hope will provide clues about the Big Bang and the
nature of the universe.

While this may be possible in the future, scientists are now
glad to see that the magnets, which are connected by six
conductors capable of transmitting up to 13,000 amps each,
are once again in working order.