The Large Hadron Collider is being prepared for its second three-year run (Image: CERN)
The
Large Hadron Collider
(LHC), the largest and most powerful particle accelerator in the world,
has started to get ready for its second three-year run. Cool down of
the vast machine has already begun in preparation for research to resume
early in 2015 following a long technical stop to prepare the machine
for running at almost double the energy of run 1. The last LHC magnet
interconnection was closed on 18 June 2014 and one sector of 1/8 of the
machine has already been cooled to operating temperature. The
accelerator chain that supplies the LHC’s particle beams is currently starting up, with beam in the
Proton Synchrotron accelerator last Wednesday for the first time since 2012.
"There is a new buzz about the laboratory and a real sense of
anticipation," says CERN Director General Rolf Heuer, speaking at a
press conference at the
EuroScience Open Forum (link is external) (ESOF)
meeting in Copenhagen. "Much work has been carried out on the LHC over
the last 18 months or so, and it’s effectively a new machine, poised to
set us on the path to new discoveries."
Over the last 16 months, the LHC has been through a major programme
of maintenance and upgrading, along with the rest of CERN’s accelerator
complex, some elements of which have been in operation since 1959. Some
10,000
superconducting magnet interconnections were
consolidated in order to prepare the LHC machine for running at its design energy.
"The machine is coming out of a long sleep after undergoing an
important surgical operation," says Frédérick Bordry, CERN’s Director
for Accelerators and Technology. "We are now going to wake it up very
carefully and go through many tests before colliding beams again early
next year. The objective for 2015 is to run the physics programme at 13
TeV."
The LHC experiments also took advantage of this long pause to upgrade their particle detectors. "The discovery of a
Higgs boson
was just the beginning of the LHC’s journey," said senior CERN
physicist Fabiola Gianotti at the same press conference. "The increase
in energy opens the door to a whole new discovery potential."
The Higgs boson, first mentioned in a 1964 paper by Peter Higgs, is linked to the
mechanism,
proposed the same year by Higgs and independently by Robert Brout and
François Englert, that gives mass to fundamental particles. During its
first three years, the LHC ran at a collision energy of 7 to 8 TeV
delivering particle collisions to four major experiments:
ATLAS,
CMS,
ALICE and
LHCb.
With the large amount of data provided by the LHC during this first
period, the ATLAS and CMS experiments were able to announce the
discovery of the long-sought Higgs boson on
4 July 2012, paving the way for the award of the 2013
Nobel Prize in physics to theorists François Englert and Peter Higgs.
By providing collisions at energies never reached in a particle
accelerator before, the LHC will open a new window for potential
discovery, allowing further studies on the Higgs boson and potentially
addressing unsolved mysteries such as
dark matter.
The ordinary matter of which we, and everything visible in the universe
is composed, makes up just 5% of what the universe is made of. The
remainder is dark matter and energy, so the stakes for LHC run 2 are
high.
CERN’s accelerator complex: Restart schedule
