Safety At The LHC

The Science of Conundrums: The Almost Thermonuclear LHC

A discussion on safety at the LHC. Stefan Scherer in Frankfurt, a physicist, science writer and co-author of the physics blog Backreaction, comments: ". . . If something goes wrong, that may wreck the billion euro installation in the tunnel - worse enough - but it would not result in a a 007 like explosion of Dr Blofelds underground lab. . ." See p 13 at this LINK for the full dialog.

The Almost Thermonuclear LHC

What could go wrong with 2 x 27 km of beam pipes? The engineering and theoretical worries have been addressed from many angles. CERN has constructed a remarkable machine with many key safety features built in. Speculations on what might happen when the LHC is switched on are all in the realms of theory and lessons learned and extrapolated from much less powerful colliders. No real guarantees on what to expect from a unique experiment. Beyond the public discussions, from my overview, there's one big thing that hasn't surfaced in seminars and published papers or the media.

At the LHC you've got all the ingredients for a two stage thermonuclear proton fusion and trigger for a helium fusion bomb. The protons are hydrogen stripped of electrons in the beam pipes and the helium is the coolant for all the superconducting magnets in the main ring and in the giant detectors like ATLAS.

The helium is an enormous amount of gas chilled and compressed down to 60 metric tonnes of superfluid helium. Protons are in abundant supply, circulating in the ring at 99.99% of light speed in opposite directions, in nearly 3,000 bunches of about a 100 billion per bunch per beam line or 6,000 x 100,000,000,000 or 600 trillion protons in the system.

These aren't ordinary protons. Because they've been accelerated to near light speed, each proton has 7 TeV of energy, or 7,000 times more energy than a proton at rest. Recall what Einstein said about bodies accelerated to speeds approaching light. They gain mass! And recall the Lorentz contraction. At these phenomenal speeds, bodies are foreshortened, appearing smaller than when at rest.

Has something so basic in physics been overlooked? A great number of very heavy protons, enormously compressed, at least 1200 million colliding every 25 nanoseconds, travelling at 11,245 laps around the ring in one second, so all 600 trillion would mingle within say ATLAS in less than a second. Of course not, but then what if there were more collisions and pileups, so that
the anticipated small fireball burned all the protons, expanding and overwhelming the detector, rupturing a helium line? At expected temperatures of the proton fireball, more than 100,000 times the core temperature of the sun, wouldn't that be enough to fuse the captured helium present?

Rather an unfortunate choice to use fusible helium as the coolant, like the location of the LHC near a big city, Geneva and much of the UN apparatus there.

Even if CERN did achieve a small fireball, a small helium leak would fuel the fusion reaction and you would have, not an LHC, but a nuclear fusion reactor. The enormous magnetic fields might contain the plasma for a while, but with the detectors not designed to be reactors and many combustibles present in the calorimeters, like silicon chips and fiber optics, any detector could burn from the inside out. To shut off the supply of helium would be difficult, depending where the valves are. It would be a runaway situation with helium flooding the test cavern in short order. Working at the world's largest cryogenic LNG plant in the 1980's, I have first hand experience of what can go wrong even when you have the best engineering and operations people. Since the plant was on a stretch of sandy beach, if something big went wrong, then we would have only blown up about $2 billion dollars and a beautiful high tech machine. Not Geneva or the UN or a lot of fine Swiss watches and a major banking center and who knows how many people.

This type of proton-helium nuclear explosion is certainly possible. Hydrogen bombs work in a similar way. An initial small nuclear explosion fusing a supply of low molecular weight gas. Thermonuclear bombs are currently the most powerful by far.

In order for the LHC to blow up, the question is whether or not there is enough proton mass present to produce a big enough fireball to rupture these tiny refrigerator freezer type channels in the detectors containing helium. In a worst case scenario would we have an explosion, a fireball, a nuclear explosion or plasma erupting? How would a helium fusion bomb compare with a hydrogen bomb? Just how massive could it be given a 60 tonne contained supply of helium. Could it all fuse and be far more catastrophic?

These are serious and important questions, not posed by the media or CERN, at least not publicly. We need an answer soon before the LHC starts up this summer. A lot of people's lives could be at risk. If there is or isn't a danger, we should have the facts and the math from CERN. Any physicists care to comment?

Other Headaches In Particle Physics

Another piece of ATLAS. Where do neutrinos fit in? Not in the Standard Model. Nor whatever happened to antimatter, when the Big Bang supposedly released equal amounts of matter and antimatter, which should have annihilated each other, leaving only energy behind. Why does the Universe obviously prefer matter? And why isn't the Universe homogeneous everywhere like a field of stars without galaxies if it expanded out from an orange-sized ball? Why is it expanding when gravity would tend to stop expansion, indeed reverse the Big Bang into the Big Crunch? Well there are theories and theories about all this. At the LHC they've got a long list of questions about theories and they think some are bound to be answered from data they expect and maybe don't expect.

Meanwhile Astrophysics seems to be overtaking Physics and Particle Physics. It's like the revenge of Astrophysics. With only 4% of the matter of the Universe accounted for, astrophysicists say, the rest invisible, maybe there wasn't a Big Bang after all? Anyway 96% of the Universe right there, doesn't fit into the Standard Model. It's only a bit of background microwave energy Science leans on and some expansion, the red shift well noted, that is the proof for the Big Bang theory. Besides, where did the orange come from? While particle physicists are attending endless meetings at CERN, the impossible is happening all around us in space.

You might remember black holes being popular as a simple theory of matter accumulating into an unimaginably dense body so small it might appear like a massless black hole, sucking up more matter and energy. After many years of uncertainty, some have been found inside galaxies thanks to space-based telescopes like the Hubble and recently Spitzer and Chandra. But then the theory suggests they're unstoppable and would eventually absorb the galaxies they're in and there are still perhaps a 100 billion or more galaxies and no sign of any big trouble. Then a spectacular find, a black hole from a galaxy 3C321, the death star galaxy in the news last December, erupting a jet of radiation 850,000 light years long, striking another smaller galaxy about 20,000 light years away, and 1.4 billion light years from us.

A black hole releasing considerable energy, except perhaps into some other fantastic dimension, was entirely unpredicted. Only some suggestions of black holes possibly exploding, and Stephen Hawking's 1974 theory that a black hole could decay via a thermal radiation created by the black hole itself, slowly leaking (still unconfirmed) Hawking radiation. If 3C321 can happen, then what of unexpected results at the LHC?

Now of course someone at NASA or somewhere is bound to post a patch for black hole theory and dine on the celebrity status for a lifetime, like all scientists dream of. But how would you patch Geneva, Mount Blanc and a lot of great ski resorts popular with grad students, postdocs and trendy physicists at CERN, patch that and all of Switzerland and a good chunk of France, say to Marseilles?

Some are worried over at CERN. Not officially, like don't bite the hand that feeds you. There's an unusually smooth PR operation going on at CERN to keep things humming, even professional seminars on how to handle the media in Spotlight on the media. Mind you everything is above board and transparent with terrific open access to most anything going on at CERN. You won't find any conspiracy or conspiracy theorists. If you dig hard enough into private online blogs, you'll discover a few cool and amused dissenters. There's edgy good fun in cold war rivals, ATLAS and CMS, each calling the other the enemy. And gallows humor, like the Doomsday Machine. All they need is a Dr Strangelove. Don't worry about black holes. There's this special radiation.

And if you've still got a headache, be brave. Take one LHC with a little superfluid helium before bedtime and you should be fine in the morning.

Physics' Big Headache Or Why Build The LHC

Testing thousands of lead tungstate crystals for ECal. The problem is the Standard Model in Physics which seeks to unify the weak force, the strong force and the electromagnetic force, 3 of the 4 major forces, gravity left out because it has so little effect on the subatomic scale, particle physicists think. Anyway they're obliged to, because gravity refuses to fit in.

What they've got since the 1960's is chunks of theories that seem to work fine as parts of the puzzle, but at the very least other pieces are missing. And if they don't find them, then the Standard Model might be no better than a Ptolemaic theory of sun and planets going around the earth.

The Standard Model is messy too. It's not simple and elegant like Einstein and Newton. It won't give us values for particles. They have to be arrived at through experiments with colliders like the LHC. In the breakthrough Electroweak Theory, uniting both electromagnetism and the weak force, add any value like mass to these equations and they don't work. Then all particles have no mass. And they should all travel at the speed of light. This is the absurd reality of particle physics. But it won a Nobel Prize at CERN, so experimentally confirmed in part. What are we doing then, imagining the Universe? Enough to give any physicist some sleepless nights and a cosmic hangover in the morning.

But physicists cling to the Standard Model because they don't have anything else except stranger theories without a shred of experimental proof. All the Standard Model needs is some improvement, like a new theory to confer mass on particles from the outside. Enter the theoretical Higgs boson. At CERN they're hoping to find it with the LHC, or maybe create a Higgs field from a hadron fireball. Gone are the days of simple atom smashing. CERN actually wants to simulate on a small scale with colossal energies, what conditions were like 13.7 billion years ago, when there must have been a Higgs field, a billionth of a second after the Big Bang.

To do so a stone's throw from the Geneva Airport is taking an incalculable and unnecessary risk.

Who wants a theoretically dangerous anything in your backyard? Maybe if there were some real benefit, but is anyone really the wiser or better off when a $10 billion theory is confirmed or denied, and of interest only to a small group of physicists?

It's about as pointless an exercise as the Tower of Babel. Granted it's way more sexy. Science Porn, Boing Boing calls it.