Doom-saying kooks, time to start screaming again
Get lost
By Paul Rincon
Science reporter, BBC News
The Large Hadron Collider (LHC) experiment has been re-started after a
hiatus of 14 months.
Engineers have now made two stable proton beams circulate in opposite
directions around the machine.
If all continues to go well, the team might even try to increase the
£6bn ($10bn) collider's energy to record-breaking levels this weekend.
The LHC is housed in a 27km-long circular tunnel built about 100m
beneath the French-Swiss border.
The experiment is designed to smash together beams of protons in a bid
to shed light on the nature of the Universe.
Among other things, scientists will search for signs of the Higgs
boson, a sub-atomic particle that is crucial to our current
understanding of physics. Although it is predicted to exist,
scientists have never found it.
Dozens of giant superconducting magnets that accelerate the particles
at the speed of light have had to be replaced after faults developed
just days after the collider was inaugurated last year.
Operated by the European Organization for Nuclear Research (Cern), the
LHC will create similar conditions to those which were present moments
after the Big Bang.
"It's great to see beams circulating in the LHC again," said Cern's
director-general Rolf Heuer.
"We've still got some way to go before physics can begin, but with
this milestone we're well on the way."
Engineers sent their first beam all the way round the LHC's
circumference after 1930 GMT on Friday.
The beams themselves are made up of "packets" - each about a metre
long - containing billions of protons. But they would disperse if left
to their own devices.
Electrical forces had to be used to "capture" the protons. This keeps
them tightly huddled in packets, for a stable, circulating beam.
Engineers had not been expected to try for a circulating beam before
0600 GMT on Saturday.
James Gillies, Cern's director of communications, told BBC News: "It
happened faster than anyone could have dreamed of."
"Everything went very smoothly."
Record attempt
Dr Gillies said that if everything continued to go well, Cern might
try to reach a record-breaking beam energy of 1.2 trillion electron
volts this weekend.
Only the Tevatron particle accelerator in Chicago, US, has approached
this energy, operating at just under one trillion electron volts.
But other team members want to keep the beam circulating at low energy
and try for the machine's first proton beam collisions.
"The LHC is a far better understood machine than it was a year ago,"
said Steve Myers, Cern's director for accelerators.
"We've learned from our experience, and engineered the technology that
allows us to move on. That's how progress is made."
There are some 1,200 superconducting magnets which form the LHC's main
"ring".
These magnets bend proton beams in opposite directions around the
tunnel at close to the speed of light.
At allotted points around the tunnel, the proton beams cross paths,
smashing into one another with enormous energy. Large "detector"
machines located at the crossing points will scour the wreckage of
these collisions for discoveries that should extend our knowledge of
physics.
# 1 - 14 quadrupole magnets replaced
# 2 - 39 dipole magnets replaced
# 3 - More than 200 electrical connections repaired
# 4 - Over 4km of beam pipe cleaned
# 5 - New restraining system installed for some magnets
# 6 - Hundreds of new helium ports being installed around machine
# 7 - Thousands of detectors added to early warning system
Engineers first circulated a beam all the way around the LHC on 10
September 2008.
But just nine days later, an electrical fault in one of the
connections between superconducting magnets caused a tonne of liquid
helium to leak into the tunnel.
Liquid helium is used to cool the LHC to its operating temperature of
1.9 kelvin (-271C; -456F).
The machine has been shut down ever since the accident, to allow
repairs to take place.
Professor Norman McCubbin, from the UK's Rutherford Appleton
Laboratory in Didcot, added: "I'm sure every particle physicist has
been feeling just a little bit impatient as the 're-start' of the LHC
has drawn nearer. It's great to see beams circulating again."
The damage caused to the collider meant 53 superconducting magnets had
to be replaced and about 200 electrical connections repaired.
Engineers have also been installing a new early warning system which
could prevent incidents of the kind which shut down the experiment.
Cern has spent some 40m Swiss Francs (£24m) on repairs to the
collider.
Paul.Rinco...@bbc.co.uk
Story from BBC NEWS:
Chris.B
> Restart for 'Big Bang' experiment
> By Paul Rincon
> Science reporter, BBC News
One word: Baguette.
Some more words:
Murphy's Law states that: A baguette cannot be accelerated to near the
speed of light without serious consequences to the space time
continuum.
A few more:
"Trust us. We know what we are doing."
Aye-aye, Bosun! :-)
whitebread
"Chris.B" <chr...@nypost.dk> wrote in message
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