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copied from:
http://www.msnbc.msn.com/id/43286330/ns/technology_and_science-science/


CERN scientists refine antimatter 'trap'
'This is a big step in demonstrating what we can do and where we can go'

The Associated Press
updated 6/5/2011


-GENEVA — Nuclear scientists announced Sunday that they have found a way to "trap" for more than 15 minutes elusive antimatter atoms that used to disappear after a fraction of a second.

That will give scientists at the European Organization for Nuclear Research time to study the atoms properly, in the hope of understanding what happened during the first moments of the universe.

The achievement is a significant improvement on earlier attempts to trap antihydrogen, which like all antimatter has a tendency to disappear before scientists have time to examine it.

"We went from two-tenths of a second to 1,000 seconds," said American scientist Jeffrey Hangst, a spokesman for the ALPHA research team working at the world's biggest particle physics lab — known by its French acronym CERN — on the Swiss-French border.

The team improved the efficiency of the antimatter trap by cooling antihydrogen atoms down to less than 0.5 degrees above absolute zero. Their research was published online in the journal Nature Physics.

Hangst said extending the lifetime of antihydrogen means scientists can be sure it has enough time to settle so it can be probed and compared with hydrogen atoms. The team will begin firing microwaves and then lasers at trapped antihydrogen later this year.

Phillip F. Schewe, a spokesman for the American Institute of Physics, said refining the antimatter trap was a great feat of physics engineering.

"But in a sense it does represent an incremental improvement rather than the achievement of something new," said Schewe, who wasn't involved with the work. "Now they'll have to trap greater number of atoms."

Hangst said the ALPHA team has already trapped about 300 antihydrogen atoms. The more they trap, the easier it is to conduct experiments on antihydrogen.

"This is a big step in demonstrating what we can do and where we can go," he said.

Understanding antihydrogen will help solve one of the biggest riddles of physics. Theorists say both matter and antimatter must have been created in equal amounts in the Big Bang, but antimatter has since disappeared from the natural universe while matter abounds in the stars, planets and galaxies.

Or as Hangst puts it: "Half the universe has gone missing and we don't know why."

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http://www.bbc.co.uk/news/science-environment-13666892


6 June 2011

Antimatter atoms are corralled even longer

Jonathan Amos By Jonathan Amos Science correspondent
BBC News



Scientists have succeeded in trapping atoms of anti-hydrogen for more than 15 minutes.



The feat is a big improvement on efforts reported last year that could corral this mirror of normal hydrogen for just fractions of a second at best.

The researchers tell Nature Physics journal that they can now probe the properties of antimatter in detail.

This will help them understand why the Universe is composed of normal matter rather than its opposite.

Matter and antimatter are identical except for opposite charge, and destroy each other when they meet. Theory holds they should have been produced in equal amounts at the Big Bang - and yet the cosmos favoured matter over its mirror.

"We have improved the efficiency of trapping compared with what we published last November," said Jeffrey Hangst, who works on the Alpha collaboration at the Cern particle physics laboratory in Switzerland.

"In order to make these studies, it surely helps to have more atoms and we've made an improvement of about a factor of five. We announced 38 trapped atoms [last year]; we've now studied about 300 which have been held for varying amounts of time."

Antimatter is a mirror image of the matter that makes up the world we are familiar with
"Normal" matter consists of particles, while antimatter is made up of antiparticles
Antiparticles have the same mass as particles of matter, but carry the opposite electric charge
For example, the negatively charged electron particle has an anti-matter "twin" called a positron, which carries a positive charge
When particles of matter collide with antiparticles, they destroy each other in a process called annihiliation
The modern theory of anti-matter began in 1928, when physicist Paul Dirac predicted the existence of antielectrons
In the first instants after the Big Bang, the Universe is thought to have been balanced with equal amounts of matter and antimatter
By one second after the Big Bang, the antimatter had largely disappeared, leaving normal matter to dominate the Universe
An experiment at the Large Hadron Collider called LHCb aims to explore the mystery of why this happened

In normal matter, a hydrogen atom comprises an electron bound to a proton. In the anti-form, the mirror of an electron - a positron - is bound to an antiproton. Together, these two particles make a neutral anti-atom.

Particle physics labs such as Cern can make antimatter particles routinely but until now they have had great difficulty in retaining this material because it will instantly annihilate on contact with conventional containers made of normal matter.

The Alpha collaboration, however, has developed a frigid, evacuated, "magnetic bottle" that allows its scientists to enclose anti-hydrogen particles and draw out the time before they are destroyed. Initially this was a mere two-tenths of a second but the team says it has increased this period more than 5,000-fold.

The significance is that it allows the antiparticles to relax to their ground state.

"If you think of an atom as a little planetary system with the electron orbiting the nucleus - or in our case, a positron orbiting the anti-proton - the ground state is the one where the electron or positron is closest to the nucleus," explained Dr Hangst.

"We think we make our anti-hydrogen in excited states; in other words the positron is at a larger distance from the nucleus. It has more energy. That's not the state we want to study. It takes some fraction of a second for these atoms, once they're produced, to get to the ground state.

"If you hold them 1,000 seconds, you can be quite sure they're in the state you want to study; and this is the first time that anyone can make that claim."

The Alpha team now plans to use microwaves to probe the anti-hydrogen atoms' internal structure.

They would also like to see how these particles behave in the gravitational fields that exist in our "normal Universe".
Artist's conception of an anit-hydrogen atom being released from the trap after 1,000 seconds An artist's conception of an anit-hydrogen atom being released from the trap after 1,000 seconds

This latter experiment will require laser manipulation and even colder conditions. At the moment, the anti-hydrogen atoms are held in their bottle at just half a degree above absolute zero. For the gravity experiments, conditions would need to be a few thousandths of a degree above the theoretically coldest achievable temperature.

"The question is very simple: do matter and antimatter obey the same laws of physics? That's a very simple question, but a very profound one," Professor Hangst told BBC News.

"The Big Bang theory says there should have been equal amounts of matter and antimatter at the beginning of the Universe. Nature kinda 'took a left turn' and chose matter.

"We know that we're missing something from the current model of how the Universe works; we just don't know what that is. So, anytime you get your hands on antimatter you should look very carefully to see if you can find something different."

One task is to increase the number of anti-atoms in the trap. The team says this is more useful now than trying to increase the anti-atoms' longevity which is ample for the planned experiments.

But collaborator Dr Makoto Fujiwara says this could change: "Our current apparatus is not optimised in fact for even longer life-time.

"It's possible that we have them much longer already but it will be limited by the vacuum - the residual gas in the system - and in the future I think we want to optimise that for even better life-times because in some cases we may want to hang on to the antimatter longer."

The Alpha collaboration originally posted news of its 1,000-second confinement earlier this year on the the Arxiv repository. The research has now been formally published in Nature Physics.

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http://www.smartplanet.com/blog/intelligent-energy/the-practical-uses-of-antimatter/6825

The practical uses of antimatter

By Mark Halper

June 6, 2011

It was a banner weekend for antimatter fans, as CERN announced that it trapped entire atoms of the feisty, elusive stuff for over 16 minutes.

That’s the longest time that anyone has managed to hold on to antimatter atoms – they are famously difficult to corral because antimatter annihilates whenever it encounters matter.

Geneva-based CERN made the usual proclamation that accompanies antimatter breakthroughs: we are now one step closer to solving the mega mysteries of nature and the universe. The Big Bang should have created an equal amount of matter and antimatter. But antimatter is scarce; so scientists hope to learn what happened to it and how it works. That in turn could shake up our fundamental understanding of ordinary matter.

“Half of the universe has gone missing, so some kind of rethink is apparently on the agenda,” said CERN’s Jeffrey Hangst in announcing the 16-minute achievement.

There’s no denying the profound possibilities of CERN’s advance, so I will leave that discussion to others.

Instead, I’ll take this opportunity to explore another side of antimatter: its practical or, even, everyday, side.

One thing for sure about antimatter is that it explodes when it meets matter. Harness that, and the possible uses are limitless.

Take hospital PET scans for example, which are probably the most common application of antimatter. The “P” in PET stands for positron, which is a subatomic, antimatter particle. The medical profession uses Positron Emission Tomography to inject positrons into a brain and watch for gamma rays that flash when the positrons encounter electrons of normal matter. The two destroy each other, giving off a light pattern that is different in an afflicted brain than in a normal one, thus revealing neurological aberrations.

Likewise, researchers around the world are trying to put positrons to work exposing weaknesses and abnormalities in all sorts of materials and things, ranging from metals and semiconductors to aspirin, ice cream and potato chips.

When I last spoke with experts on this subject – admittedly several years ago - I was intrigued by the possibilities. Physicist Paul Coleman at the University of Bath in England told me then that positrons naturally find the atom-sized holes in the crystal lattices that make up a metal. Gamma ray detectors, like in a PET scan, could note where the positrons settle, thus revealing weaknesses. As Coleman said, “a crack will always start in atomic scale, which turns into a bigger crack which leads to your airplane wing falling off.’’

That is an extreme example. But the point is that by discovering atomic level vulnerabilities, researchers can develop stronger materials for building electronic chips, planes, trains, automobiles, skyscrapers, bridges, roads and so on.

Coleman is no a one-off crackpot. Plenty of other physicists and engineers are looking into this.

Want proof? Go to the website of none other than the Positron Annihilation Community. That’s right, the Positron Annihilation Community. Everyone has to have a community these days, so you wouldn’t want to discriminate against positron annihilators, would you? The website invites you to “learn about the possibilities of practical application of Positron Annihilation” across all sorts of fields including metals, semiconductors, dielectrics and polymers.

Professor David Parker at the University of Birmingham is a physicist on the vanguard of positron research. His group is producing positron emitting isotopes “that are used to tag tracer particles both for studying real-time flow in industrial processes and for diagnosis in hospitals,” according to his web page. “By detecting the back-to-back emission of gamma-rays that follow the annihilation of a positron and electron pair, imaging with millimetre precision in applications ranging from the lubricant distribution in engines and dynamic studies of fluid flow through geological samples is possible,” the page states.

Today’s positrons tend to come from expensive cyclotrons that create isotopes of elements that in turn emit positrons as they decay.

Over the years companies as varied as Intel, Unilever, United Biscuits and Rolls Royce have investigated the use of antimatter in everything from making a stronger electronic chip to a crispier potato chip, and from a better aspirin coating to smoother engine oil.

And let’s not forget that antimatter, with all its explosiveness, was the fuel source that so effectively hurtled Star Trek’s Starship Enterprise across galaxies. Of course, Captain Kirk didn’t have to worry about the price of antimatter – in 1999, NASA estimated that it costs $62.5 trillion to produce one gram of antimatter. But perhaps it is food for thought for those who dare to boldly go to a post-electric, post hydrogen world of locomotion.