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Antimatter Gamma Ray Bursts

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cduma

Wed Nov 25 2009, 12:19AM

Registered Member #1822 Joined: Fri Nov 21 2008, 08:04PM
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Posts: 300

After reading this article I began to wonder if my 28KJ Capacitor bank may be able to reproduce the above^. I would very much like to have a small jar of antimatter so that I could hold the world hostage. Any ideas about how I could for one, measure gamma ray bursts?

Frosty90

Wed Nov 25 2009, 01:21AM

Registered Member #1617 Joined: Fri Aug 01 2008, 07:31AM
Location: Adelaide, South Australia
Posts: 139

Do these gamma bursts originate in the upper atmosphere? Or closer to the ground? Maybe you'd have to create a discharge in a low preassure environment. I suspect that a 'home-brew' attempt to recreate it would require some fairly fancy detector equipment to sort it out from the background radiation. But it would be immensley cool to re-create this phenomenon.

Cheers
Jesse

cduma

Wed Nov 25 2009, 05:48PM

Registered Member #1822 Joined: Fri Nov 21 2008, 08:04PM
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Posts: 300

Clouds (that produce lightning) are not very high up except for the very top of that really nasty one that makes all those twisters.

Other than holding the world hostage to the tune of one Bugati it would be really neat to study gravity waves which in theory accompany large gamma ray bursts. Unfortunatly the only device capable of measuring gravity changes in real time that I know of has a rather prohibitive cost. It operates similar to how noise cancelling headphones do but, it uses lasers aimed at eachother and the beams are aligned so perfect that they cancel each other out and a gravity wave will change the distance between them just enough to cause a visible burst of light. Just imagine how difficult it would be to align two lasers EXACTLY 560nM*10^XX apart. I dont remember what frequency the lasers are so I just picked 560nM because it sounded familiar...

cduma

Wed Nov 25 2009, 05:49PM

Registered Member #1822 Joined: Fri Nov 21 2008, 08:04PM
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If anything productive arises from this thread I will be absolutely amazed. This thread is more for fanciful thinking.

MinorityCarrier

Wed Nov 25 2009, 06:33PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

I was thinking, fancifully, that there must be some potent pharmacologicals being used to fuel this thread.

cduma

Wed Nov 25 2009, 08:20PM

Registered Member #1822 Joined: Fri Nov 21 2008, 08:04PM
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Yeah! I found some pills! And I ate them all! There were red ones, blue ones, all sorts of colors and they were yummy.

wylie

Thu Nov 26 2009, 03:19AM

Registered Member #882 Joined: Sat Jul 07 2007, 04:32AM
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<Armchair Nuclear Physicist On>

The whole thing sounded fishy, but after a little checking, apparently it's widely accepted that lightning produces actual gamma rays.

Ok, so we have the signature of e-/e+ annihilation from lightning....but where are the positrons coming from in the first place? I was under the impression that all the EM output from lightning was from electron excitement/relaxation, which would make it (very hard) x-rays, not gamma rays.

Is it possible that lightning could excite an electron far enough that when it transitions back down to the ground state, it would emit an x-ray of high enough energy/freq to allow pair production? Could the discharge possibly accelerate some electrons hard enough to emit some synchrotron/Bremsstrahlung that enables the pair production?

In any event, as far as antimatter-in-the-lab goes, this seems like an inefficient, brute force approach. All that energy going into heat and visible light. Probably easier to just setup a LINAC and slam electrons into an appropriate target. Or fire a megafast highpower laser onto some gold. Pyroelectric crystals look pretty cool too, but information is scant so far.

I'm not very clear on the laser+gold target method. 1.022meV corresponds to 1.21pm light (for photon-nucleus pair production; 511keV = 2.42pm, for photon-photon pair production). I was assuming that, like the photoelectric effect, frequency of light was the important factor not intensity. I can't (quickly) find construction details for the Titan laser, but it looks like it's TI:Sapphire, so its not producing extremely hard x-rays. Is this some non-linear effect achievable even with visble/UV light, provided you can dump enough power in a small enough time and space? Would seem to be what they're saying with: "When a short pulse with intensity greater than 10^19 watts per square centimeter strikes a target, electrons with energies up to 3 megaelectronvolts are created."

From another article about Titan, specifically about positron creation: "As they move close to the gold nucleus, the electrons each break apart into a lower-energy electron and its anti-matter opposite, a positron. The high-energy electrons would naturally break down into matter and anti-matter pairs; the gold simply speeds up the transformation."

I'm really not sure what physical process they're talking about there, anyone have a clue? Still, seems plausible that electrons accelerated to 3meV could be involved in pair production somehow, since it only requires double the rest mass/energy of an electron (511keV*2). Could it just be the idea from above: The 3meV electron transitions to a lower state, letting out a 1.022meV x-ray which triggers the pair production?

Now, skipping ahead to when you have your petawatt laser facility completed, we need to consider storage of your positrons next. An ultra-hard vacuum, materials that won't out-gas at all, and some serious trapping fields. Actually, sounds easier than the laser ;) Then we can work on the anti-proton facility next-door, and we'll have anti-hydrogen in no time. At which point i propose we start working on fusion of anti-hydrogen for the production of heavier anti-elements. Once we get upto anti-carbon, we can construct some microscopic circuit elements and study positron current flow, which i think would be Too Cool For School.

We're only a few steps away then from harnessing the positron flow from my singularity reactor concept. (feed matter to a micro-singularity to produce jets of 1.022meV photons for pair-production, and divert the resultant charged particles to the (matter and antimatter) loads. Then let them annihilate on the other side, and use a yet-to-be-discovered way of harnessing work from compton scattering by the resulting 511keV photons. Once the photon's have scattered down to UV energies, they're directed through layers of photovoltaic nanoantennae. Talk about energy efficiency. I'm betting the artificial singularity warpcore in romulan warbirds worked along those lines ;) )

Back to reality now. To detect any possible gamma rays from a discharge, looks like the prevailing technique is still scintillators and photomultiplier tubes (or avalanche photodiodes) as in PET scanners.

I think if you could get the discharge from your 28KJ bank to mimic a lightning bolt, it would probably be worth looking for super-high-energy photons. Aren't Marx generators typically used to simulate lightning though? (Maybe a more convenient and efficient route for the search?)

</Armchair Nuclear Physicist Off>

plazmatron

Thu Nov 26 2009, 05:04PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

There are two possible sources of positrons in a lightning storm.

The first is high energy heavy ion collisions in the upper atmosphere directly above the stroke itself ( "jets" and "sprites"),
that may produce positrons.

The second is that is was recently postulated that lightning storms may be induced by cosmic rays, which will happily produce positrons, along with other subatomic bric-a-brac.

Les

Proud Mary

Thu Nov 26 2009, 07:57PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Setting aside the origin of any gamma ray bursts detectable at ground level, I see it as being no easy matter for even the well equipped amateur to distinguish them from terrestrial gamma rays, or even from cosmic muons also arriving from skyward.

Vertical stacks of coincidence counters could demonstrate that the rays came from skyward, and if one filtered out the gamma rays from one stack by shielding it under a lead block so that only muons could be detected , then one could compare the output of this with an unshielded stack, and infer the relative ratios of gamma rays and muons coming from skyward.

But attempting to measure their energy seems very much more difficult without sophisticated and costly equipment.

If these gamma ray phenomena are relatively infrequent, then the task would be more difficult still.

It's not something on which I'd have the time, money or skill to attempt.

Fri Nov 27 2009, 04:38AM

Registered Member #2372 Joined:
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Posts: 62

If you wanted to see if you were having pair production you need to use a coincidence detection system like someone mentioned that is used for PET scans. To make antimatter (positrons) you just need 1.022MeV photons and sometimes they would have a collision and pair production would result. You could make those with a MV marx generator a vacuum diode and a high Z target. Some of them would probably interact with something and make positrons. You could also do it with an ultrahigh intensity laser, the electrons in the field become relativistic and these could be used to make high energy photons. Or you can make really high energy electrons in a laser wakefield accelerator, but I dont think any home experimenter can build one of those lasers.

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