Lets talk Anti-Matter

[silverpig]

Originally posted by: DrPizza
I do avoid some of the heavier stuff in here... It's simply been too many years (around 20) since I did a lot of the upper level physics stuff and EE stuff; I rarely use any of that knowledge.

Regardless, concerning the matter/antimatter annihilation: Why is it that particle accelerators give off a tremendous amount of radiation as well as other particles upon the matter/anti-matter decay? (I do realize that much of the radiation is emitted as the particles are accelerated) Last time I was at the Wilson Synchrotron Laboratory at Cornell (about 4 years ago), they were conducting a lot of experiments that were using the gamma radiation released which they considered, more or less, as a by-product. Intuitively, after touring their facility and noting all the cautions they took to make sure no one was anywhere near the collider when things were going, I figured there was a lot of radiation.

Other questions: if matter/anti-matter annihilations don't produce gamma radiation, then why have we searched the universe for the tell-tale gamma radiation that would indicate such interactions... The lack of this radiation has led us to the conclusion that the universe is, in fact, pretty much made up of matter. (Not anti-matter)

Perhaps I was a bit short in simply stating E=mc^2 and E=hf... however, I'm still fairly convinced that the annihilation does release gamma radiation.

And, if that's not enough, then how does positron emission tomography work? Does it detect the neutrinos that are given off after a positron electron reaction?


pre-empted edit: OHHHHHHHHHhhhhhhh, I see what you mean.
Trace radiation left behind as in some uranium isotopes floating around...

Sorry!! You're correct. Hey, it was almost 2am last time I checked this thead, and it's after 3am now here... I'm a bit tired... I see how I misunderstood the op.

incidentally, at particle accelerators, they commonly collide electrons and positrons, and wind up with lots of interesting particles to study... However, I've been led to believe that much of the energy to form these particles comes from the kinetic energy of the initial particles.. In the annihilation of, say, an iron nucleus with anti-iron, would/could enough energy be present to result in the creation of other particles, including some radioactive particles? Or, when looking at such an interaction, would you simply view it as a bunch of individual proton-antiproton and neutron-antineutron reactions? Or, does it go as deep as quark/anti-quark reactions??

First, we're a LONG way away from anti-iron. Anti-hydrogen we can do, but even anti-deuterium is probably out of our reach.

Second, yeah you would easily have enough energy in that reaction to produce things like muons (eventually electrons), and pions etc. That actually is probably what would happen if you had that much energy in photons in one place.

Third, in iron/anti-iron you would probably have a few anti up quarks on the anti-iron nucleus hit some up quarks on the iron nucleus, annihilate, and push the remnants of the two iron nuclei apart. You would probably end up with some shattered iron nuclei (radioactive carbon and oxygen, lithium, beryllium, helium... i dunno). It wouldn't be a simple "all the protons and anti-protons get turned into gammas and same with the neutrons and electrons" type thing for sure. So yeah, if you had iron/anti-iron then there definitely would be radioactive material left over.

Hydrogen/anti-hydrogen is another story though. Actually, if you just dropped a canister full of anti-hydrogen into the atmosphere and exposed the contents to matter, then I would say that you probably would be left with radioactive particles as you would have a nitrogen nucleus hit an anti-proton as your dominant reaction. This would leave radioactive carbon 13, providing the nucleus doesn't undergo fission. If that occurred, you'd probably have lithium 6 and lithium 7, or some radioactive combination of helium and beryllium I guess.

Of course, then there's the possibility of having carbon 13 with a couple of pions if the proton and anti-proton don't completely annihilate...

Too many possibilities

 

[MrDudeMan]

Originally posted by: silverpig

Either way, it's just nitpicking. You're right about what you said: the reaction itself only produces ionizing radiation in the form of photons and doesn't produce any radioactive materials directly, but if you were to do this in an atmosphere, then yeah, there'd be radioactive material left over.

i agree :thumbsup: and sorry about the nitpicking.

drpizza, you are definitely right in that it does release gamma radiation. i was too brief with my words but i meant it does not release radioactive particles. there is a big difference as im sure you are aware, so we were arguing different points.

 

[AluminumStudios]

There would be a big blast of gamma radiation and spray of particles that pop into existence from the energy levels (based on e=mc^2) and that would fry everything at that instant, but there wouldn't be decaying particles leftover releasing radiation ... which is the case in a nuclear fission explosion.

Well, maybe superheated gas might emit some xrays of the explosion was big enough ...

 

[AgentJean]

So a simple answer to the question.
If someone were to detonate a anti-matter/matter warhead on say Iran.
Will I be able to have a victory BBQ a few days later without the risk of radaiton poising like I would dropping a normal nuke?

 

[Gibsons]

Originally posted by: AgentJean
So a simple answer to the question.
If someone were to detonate a anti-matter/matter warhead on say Iran.
Will I be able to have a victory BBQ a few days later without the risk of radaiton poising like I would dropping a normal nuke?

Set the normal nuke off at high altitude and you can probably still have your bbq in a few days. So long as it doesn't rain.