Sunday, November 21, 2010

CERN traps antimatter atoms

It looks like the doomsday sayers were wrong - creating antimatter didn't destroy the planet (or was it the universe?). That's hardly surprising, as antimatter pops in and out of existence all the time, and both the universe and the planet seems to still be here.

CERN has created antimatter for nearly a decade, starting in 2002, but these particles have always been short-lived as the interact with the matter around them, and disappears.

This week, however, Nature published the news that scientists at CERN has managed to contain antimatter atoms, for more than 170 milliseconds, 38 times. This was done by using a "magnetic trap"

The ALPHA claim is the first major advance since the creation of thousands of antihydrogen atoms in 2002 by a forerunner experiment called ATHENA2 and by ATRAP3 [...]. Both experiments combined decelerated antiprotons with positrons at CERN to produce antihydrogen atoms. But, within several milliseconds, the atoms annihilated with the ordinary matter in the walls of their containers.

To prevent that from happening, the ALPHA team formed antihydrogen atoms in a magnetic trap. Although not electrically charged like antiprotons and positrons, antihydrogen — like hydrogen — has a more subtle magnetic character that arises from the spins of its constituent particles. The ALPHA researchers used an octupole magnet, produced by the current flowing in eight wires, to create a magnetic field that was strongest near the walls of the trap, falling to a minimum at the centre, causing the atoms to collect there.

Creating antimatter atoms this way has proven to be much more difficult than the "traditional" way

To trap just 38 atoms, the group had to run the experiment 335 times. "This was ten thousand times more difficult" than creating untrapped antihydrogen atoms, says Hangst — ATHENA made an estimated 50,000 of them in one go in 2002. To do spectroscopic measurements, Surko estimates that up to 100 antihydrogen atoms may need to be trapped at once.

Obviously, there is some work yet to be done before measurements can be made, but according to this National Geographic article, great advances have been made since the Nature article

Since the experiments covered in the Nature study, the researchers have created many more antihydrogen atoms and held them for much longer—fodder for a future report.

According to Fajans, "We're doing much better now."

If more antihydrogen atoms can be produced and trapped for longer periods, scientists might finally be able to study them in enough detail to explain their scarcity in our universe, he added.

That's a pretty big deal. Let's hope that the progress continues.

For the original paper, you can find it behind Nature's pay-wall here

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Anonymous James said...

I'm hoping for the progress. Looking forward to find more info about this. By the way, I have a spreadsheet here if you have few things to share kindly check it out:) Thanks in advance!

November 27, 2010 3:08 PM  

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