Big science's big day
Posted: Saturday, February 16, 2008 8:30 AM by Alan Boyle
Salvatore Di Nolfi / Keystone / AP |
An onlooker watches an element of the Compact Muon Solenoid being lowered into
its underground cavern at the Large Hadron Collider on the French-Swiss border.
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The most anticipated date in physics is the day the world's biggest particle-smasher, Europe's Large Hadron Collider, reaches full power. That day had been set for last November, but a magnet mishap and other factors forced a delay until this spring. The final piece of one of the collider's mammoth detectors, the Compact Muon Solenoid, was lowered into its underground cavern just last month. And now the big day is likely to come in June or July rather than May.
The fact is that officials at Europe's CERN particle physics lab don't know to the day when the world's biggest physics project will be ready for prime time. However, they do know the day for the big celebration.
CERN's director general, Robert Aymar, is in Boston this week for the annual meeting of the American Association for the Advancement of Science - and construction progress on the Large Hadron Collider has been one of the big topics on the meeting's agenda.
The multibillion-dollar collider, which was conceived a quarter-century ago and has been in the works for more than a decade, is expected to shed light on mysteries ranging from dark matter and extra cosmic dimensions to the reasons why particles have mass and why matter won out over antimatter.
There's currently no other way to find out the answers to all these deep questions, Aymar said. "Without LHC discovery, we are stuck, and we will not go beyond what we know today," he told reporters. That's why the start-up is so anticipated.
Aymar said commissioning the machine will take months.
Physics insiders have long known that the collider's proton beams wouldn't be zipping at full blast through the collider's 17-mile-round ring until June or July - based on the construction time lines from CERN.
June was the time frame Aymar had in mind when he was asked about the start-up schedule during a Friday session on large-scale science project. But during a follow-up chat, he pointed out that you can't just press a big red button one day and expect each of the collider's beams to hit full power of 7 trillion electron volts immediately.
The rule of thumb is that 1 trillion electron volts, or 1 TeV, is equivalent to the energy expended by a mosquito in flight - which would make 7 TeV as energetic as, say, a bumblebee. The buzz of a bee may not sound like a lot. But when you consider how many trillions of protons are in that beam, the energy adds up to a bullet train going 100 mph. So it's prudent to start small and build up power gradually.
Aymar said that buildup could still start around May 21 or 22, with tests continuing for weeks after that. His aim is to have the collider conducting scientific experiments this summer.
Of course, that assumes that everything proceeds according to plan between now and then - which is not always the case (see above, "magnet mishap"). And now that sectors of the ring are being cooled down to cryogenic temperatures, any problem that needed fixing would required going through a whole warm-up/cool-down cycle.
"Quantification of the delay is three months," Aymar said - which is a geeky way of saying that a glitch in the final phase of preparations wouldn't hold up things by just a day, but rather three months at a time.
This may be why the big party - the ceremony marking the inauguration of the Large Hadron Collider - has been set for months after the scheduled start-up, on Oct. 21. French President Nicolas Sarkozy and other VIPs (including Energy Secretary Samuel Bodman) are expected to be in attendance.
No matter what happens, that date won't change, Aymar said.
And then what? Physicists have told me the first scientific experiments would probably need a year or so to come to fruition, and it could take five years to answer some of the deep mysteries mentioned above. If the answers are there to be found, that is. There's always a chance that the collider will draw a blank - that physicists won't see anything of what they're expecting to see.
"For many people, that may seem like a disappointment," said Lawrence Krauss, a theoretical physicist at Case Western Reserve University. "From a theoretical perspective, it means that every basic idea we have about the fundamental structure of matter, in some way, is wrong. And there's nothing more exciting than that."
Update for 1 p.m. ET: So how much does all this cost? As with all big-science projects, it depends. CERN says the cost of the accelerator is 4.7 billion Swiss francs ($4.3 billion), and additional CERN contributions to the experiments and project-related computing amount to 1.35 billion Swiss francs ($1.23 billion). But scores of other countries are contributing to the experiments as well, and that could add $3 billion to $5 billion to the total expense. Thus, if you're talking about CERN alone, the machine would cost $5 billion-plus, but if you're talking about the total project, the estimates are in the range of $8 billion to $10 billion.
