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Antimatter atoms produced and trapped at CERN

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Re: Antimatter atoms produced and trapped at CERN

#21

Post by ars »

jonhohle wrote: post #12
Groxx wrote: post #10

Earlier quoted context omitted.

Let the bidding war... begin! Bidding is over! The ex-antimatter goes to...

I won the auction, and all I got was this stupid matter! (ex-antimatter == !(!matter) == matter)

Your equation is wrong. Why are you negating matter twice?

If you have anti-matter it will annihilate with matter making gamma rays. Those gamma rays can then participate in pair production making an electron and an anti-electron (positron), but that only happens in a strong magnetic field.

That positron will then annihilate again if it meets an electron (maybe even the same one, but it doesn't have to be). Which would then make gamma ray, which can start the process again. You can theoretically do this over and over forever, but realistically the gamma ray will probably be absorbed in something. Also, I think the annihilation may make two gamma rays, dividing the energy.

Edit: Is your equation a joke on the english words, ex and anti?

Re: Antimatter atoms produced and trapped at CERN

#22

Post by alex_c »

The article doesn't spell it out, and I know practically nothing about the subject, but... what happens at the end of the 0.2s? Do the antimatter atoms drift out of the magnetic fields used to contain them? Do matter atoms drift in? Or is it some property of the atoms or magnetic fields? Basically, what needs to change to increase the 0.2s?

Re: Antimatter atoms produced and trapped at CERN

#24

Post by JoeAltmaier »

alex_c wrote: post #22

The article doesn't spell it out, and I know practically nothing about the subject, but... what happens at the end of the 0.2s? Do the antimatter atoms drift out of the magnetic fields used to contain them? Do matter atoms drift in? Or is it some property of the atoms or magnetic fields? Basically, what needs to change to increase the 0.2s?

They are neutral hydrogen atoms - why does a magnetic field affect them anyway?

Re: Antimatter atoms produced and trapped at CERN

#25

Post by snissn »

JoeAltmaier wrote: post #24
alex_c wrote: post #22

The article doesn't spell it out, and I know practically nothing about the subject, but... what happens at the end of the 0.2s? Do the antimatter atoms drift out of the magnetic fields used to contain them? Do matter atoms drift in? Or is it some property of the atoms or magnetic fields? Basically, what needs to change to increase the 0.2s?

They are neutral hydrogen atoms - why does a magnetic field affect them anyway?

http://en.wikipedia.org/wiki/Hyperfine_structure

Re: Antimatter atoms produced and trapped at CERN

#27

Post by icegreentea »

JoeAltmaier wrote: post #24
alex_c wrote: post #22

The article doesn't spell it out, and I know practically nothing about the subject, but... what happens at the end of the 0.2s? Do the antimatter atoms drift out of the magnetic fields used to contain them? Do matter atoms drift in? Or is it some property of the atoms or magnetic fields? Basically, what needs to change to increase the 0.2s?

They are neutral hydrogen atoms - why does a magnetic field affect them anyway?

The link under further reading (http://cerncourier.com/cws/article/cern/30577) provides some insight.

Neutral atoms still have a magnetic moment. These do interact with magnetic fields. I'm way over my head here, so won't attempt to explain more.

Re: Antimatter atoms produced and trapped at CERN

#28

Post by alex_c »

JoeAltmaier wrote: post #24
alex_c wrote: post #22

The article doesn't spell it out, and I know practically nothing about the subject, but... what happens at the end of the 0.2s? Do the antimatter atoms drift out of the magnetic fields used to contain them? Do matter atoms drift in? Or is it some property of the atoms or magnetic fields? Basically, what needs to change to increase the 0.2s?

They are neutral hydrogen atoms - why does a magnetic field affect them anyway?

The BBC article that's further down the front page at the moment brings it down closer to my level:

http://www.bbc.co.uk/news/science-environment-11773791

----

"Atoms are neutral - they have no net charge - but they have a little magnetic character," explained Jeff Hangst of Aarhus University in Denmark, one of the collaborators on the Alpha antihydrogen trapping project.

"You can think of them as small compass needles, so they can be deflected using magnetic fields. We build a strong 'magnetic bottle' around where we produce the antihydrogen and, if they're not moving too quickly, they are trapped," he told BBC News.

Such sculpted magnetic fields that make up the magnetic bottle are not particularly strong, so the trick was to make antihydrogen atoms that didn't have much energy - that is, they were slow-moving.

----

So, basically, magic. I'm just curious what the specific limitation is (but realize it may not be trivial to explain without understanding the entire containment process better).

Re: Antimatter atoms produced and trapped at CERN

#29

Post by lutorm »

alex_c wrote: post #22

The article doesn't spell it out, and I know practically nothing about the subject, but... what happens at the end of the 0.2s? Do the antimatter atoms drift out of the magnetic fields used to contain them? Do matter atoms drift in? Or is it some property of the atoms or magnetic fields? Basically, what needs to change to increase the 0.2s?

Just based on what the article says, I suspect that even at the vacuum pressures they can achieve, there's enough normal matter around that eventually one of them penetrates the field and annihilates it.

Re: Antimatter atoms produced and trapped at CERN

#30

Post by lutorm »

Dylan16807 wrote: post #19
ars wrote: post #14

I hope they will finally definitely answer if anti-matter also has anti-gravity. Not a single scientist thinks it does, but it's one of those things you just want confirmed.

I would have thought this had already been tested on antiprotons, but I'm not seeing any references for it. Just a note that results from testing anti-hydrogen for gravity should be had in the next few years. Maybe containing something so charged overwhelms gravity?

As has been alluded to, gravity is an extremely weak force, so any gravitational effect is easily masked by electroweak forces until you accumulate a very significant mass. There's no way they can measure this on a single atom.
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