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ToSeek
2005-Jun-09, 04:19 PM
The Search for Positronium (http://www.universetoday.com/am/publish/search_positronium.html?862005)


If you could look into the sky with gamma ray eyes, you'd see gamma ray bursts, and other sources of gamma radiation across the night sky. If you could fine tune your eyes to only see a very specific colour of gamma rays, the one associated with the annihilation of matter and antimatter, you'd see wash of energy, but not coming from any specific location. Astronomers using the European Space Agency's INTEGRAL space telescope have developed one of the best pictures yet of this exotic energy.

bbtuna
2005-Jun-09, 07:07 PM
If you really want to see Positronium (Ps) you should come to my lab. We make it all day long. That's what I study. Neat stuff. I have a pic of the lab here somewhere....http://www.physics.wayne.edu/~emiller/Positron/

there it is. Terrible pic of me. I wasn't told they would be taking pics of us that day. But that's where I work. It's lots of fun.

Right now I am working on writing a paper that will hopefully be published in Physical Revew Letters or Physical Review A. I've been working on it for a while and am taking a break for a bit. It's tough writing it and it's my first.

Bozola
2005-Jun-09, 07:21 PM
If you really want to see Positronium (Ps) you should come to my lab. We make it all day long. That's what I study. Neat stuff. I have a pic of the lab here somewhere....http://www.physics.wayne.edu/~emiller/Positron/


Positron Scattering Group? Dang! So that's why I keep find the bloody stuff under my couch!

First paper? Congrats!

Gsquare
2005-Jun-12, 09:16 PM
If you really want to see Positronium (Ps) you should come to my lab. We make it all day long. That's what I study. Neat stuff. ....

Nice, bbtuna. However, since you have so much extra positronium hanging around, could you please just take a little bit and drop it from the ceiling and measure how long it takes to hit the floor? It'll help settle a long standing bet we've got going around here as to whether it falls faster than 'normal' matter in a gravity field. He, he. Thanks, we'd appreciate it very much! :wink:

P.S. I promise we will help you get it published in Physcal Review. :D
G^2

Charlie in Dayton
2005-Jun-13, 09:16 AM
Positronium?

Feh.

Call me when you've managed to whip up a couple pounds of unobtainium.
:o

bbtuna
2005-Jun-13, 08:02 PM
However, since you have so much extra positronium hanging around, could you please just take a little bit and drop it from the ceiling and measure how long it takes to hit the floor? It'll help settle a long standing bet we've got going around here as to whether it falls faster than 'normal' matter in a gravity field. He, he. Thanks, we'd appreciate it very much!

Never gonna happen. The longest the stuff lasts is 142 ns. it could be a bit longer if you could create a rydberg state of the atom though...but that's not too easy. I'll work on it in my spare time :wink: .

Grey
2005-Jun-13, 08:54 PM
Here (http://www.plantext.bf.umich.edu/planner/sculpture/central/positronium.htm)'s a piece of art from one of the professors here that I've always liked.

The Bad Astronomer
2005-Jun-13, 10:35 PM
When I was working on STIS, we used it to look for positronium Lyman alpha emission in the M87 jet (http://www.badastronomy.com/bitesize/jetplane.html). It's a long story, but we were pretty sure wouldn't see it, and we didn't (Lyman alpha from hydrogen is at 1216 Angstroms, and since positronium has an electron instead of a proton, the Lyman alpha for it is about twice the wavelength, or 2432 Angstroms, smack in the middle of one of our UV filters).

But the images of the jet in the UV had never been done before, and the data was actually most useful to me to calibrate a pesky temperature-dependent dark noise we had.

I filed this work under the title "Warp Drive". :-)

ZaphodBeeblebrox
2005-Jun-14, 07:52 AM
When I was working on STIS, we used it to look for positronium Lyman alpha emission in the M87 jet (http://www.badastronomy.com/bitesize/jetplane.html). It's a long story, but we were pretty sure wouldn't see it, and we didn't (Lyman alpha from hydrogen is at 1216 Angstroms, and since positronium has an electron instead of a proton, the Lyman alpha for it is about twice the wavelength, or 2432 Angstroms, smack in the middle of one of our UV filters).

But the images of the jet in the UV had never been done before, and the data was actually most useful to me to calibrate a pesky temperature-dependent dark noise we had.

I filed this work under the title "Warp Drive". :-)

Funny Phil ...

Isn't that Always the Way Though, The Thing that Makes your Pictures POSSIBLE, is also, the Very Thing, that Keeps you, From Actually Taking the Pictures, you Most Want to Take!

Gsquare
2005-Jun-15, 03:38 AM
However, since you have so much extra positronium hanging around, could you please just take a little bit and drop it from the ceiling and measure how long it takes to hit the floor? It'll help settle a long standing bet we've got going around here as to whether it falls faster than 'normal' matter in a gravity field. He, he. Thanks, we'd appreciate it very much!

The longest the stuff lasts is 142 ns. it could be a bit longer if you could create a rydberg state of the atom though...but that's not too easy. I'll work on it in my spare time :wink: .

Not a bad idea. How about a rydberg state with spin triplet Ps and using cavity QED to suppress the spontaneous decay? 8)
Just a thought... 8-[
G^2

bbtuna
2005-Jun-16, 05:42 PM
It would actually be better to have one of the particles in an s state and the other in a p state. Since those orbitals don't overlap so much, the lifetime would be longer (or so I was told at DAMOP :o ).

John Dlugosz
2005-Jun-16, 07:27 PM
It would actually be better to have one of the particles in an s state and the other in a p state. Since those orbitals don't overlap so much, the lifetime would be longer (or so I was told at DAMOP :o ).

Also have them spinning the same way. Has to decay into 3 photons, so the probability is lower.

Jerry
2005-Jun-20, 04:14 AM
If the billions of tons per second of positrons that are annihilated in the Milky Way bulge cannot have come from classical novae or thermonuclear supernovae, then perhaps good old dark matter is to blame.

...Trotting out the usual suspects again :-?

Magic is just as good of an answer, equally enlightening.