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New antimatter atomsmashers 'may destroy themselves'
'Imagine there are all these huge bells, see,' says prof
A top British atom-smasher boffin says that next-generation antimatter accelerators being planned to replace today's Large Hadron Collider (LHC) are at significant risk of "destroying themselves", as they rend the very fabric of the universe apart in their search for cosmic secrets.
The LHC has already shown that rashly turning up the Big Knob on such machines can lead to trouble, with a faulty electrical connector on the mighty underground proton-punisher melting last year - not only bringing the titanic magno-doughnut grinding to a halt, but also releasing a fearful tide of helium superfluid, deadly stuff which crawls up walls, eels through the tiniest crack etc. Only by lucky hap did bystanding boffins escape being transformed into frosty stalagmite statues.
But apparently the next generation of particle-punchers beyond the LHC are already on the drawing board. Rather than having some kind of logical name*, the scheme is called Compact Linear Collider (CLIC). It seems that atomsmashers are a bit like gadgets, in that they sometimes shrink rather than getting bigger as they become more advanced. However the CLIC won't be that compact, as it is to be sized in the tens of kilometres.
The new design does have a cool new feature, however. Rather than simply smashing regular bits of matter together with unimaginable violence at all-but the speed of light, it will instead smash bits of ordinary matter and antimatter together. Matter and antimatter famously react together by totally annihilating each other and releasing their entire mass in the form of energy - so fulfilling the only Einstein equation many of us can easily call to mind: E=mc2. Matter-antimatter reactions are the most powerful energy release possible, making a hydrogen bomb or even a supernova look like a mild belch or troublesome hiccup by comparison.
Fortunately, the particle-molester boffins at CERN plan only to collide very small bits of matter and antimatter in the CLIC, namely electrons and anti-electrons (aka positrons). Barring unforeseen mishaps, the risk that they will blow up the Earth seems minimal.
But there is some risk, according to top Manchester Uni atomsmasher prof Roger Jones, that the wracking stresses exerted on the CLIC as it twists and warps the very fabric of space-time could destroy the machine itself. According to a university announcement:
So-called ‘wake fields’ occur during the process of acceleration and can cause particles to fly apart.
The particles are travelling at extremely high energies – and if they are subjected to these wake fields, they can easily destroy the accelerators.
“An electron-positron collider is the natural successor to the LHC and it turns out the wake fields are much more severe in these linear collider machines," says Jones.
“Indeed, acceleration of particles to ultra-relativistic energies over several tens of kilometres in the proposed Compact Linear Collider (CLIC) poses several significant accelerator physics challenges."
Jones says he has the answer, though.
“If you have a collection of huge bells all ringing at slightly different frequencies or tones, the amplitude or ‘wave height’ of the overall sound heard will be markedly smaller than that heard if they all ring at the same tone," he explains. "This method is very efficient and structures built in this manner are known as a Damped Detuned Structures (DDS).
“Detuning is perhaps more elegant than heavy damping, as it also enables the position of the beam to be determined by the quantity of wake fields radiated by the beam," adds the prof. "In this way a DDS accelerator removes the wake fields and has its own built-in diagnostic.”
Jones' plan for safely designing the antimatter atomsmashers of tomorrow are to be published shortly online under the title Wake field Suppression in High Gradient Linacs for Lepton Linear Colliders in the journal Physical Review Special Topics - Accelerators and Beams. ®
* Even Larger Collider, God-Damn Bloody Enormous Collider, You Thought the LHC Was Large But That's Just Peanuts to This Baby etc.