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posted by martyb on Wednesday August 04 2021, @09:29AM   Printer-friendly
from the going-to-need-more-dilithium-crystals dept.

Laser pincers generate antimatter by recreating neutron star conditions:

In principle, antimatter sounds simple – it’s just like regular matter, except its particles have the opposite charge. That basic difference has some major implications though: if matter and antimatter should ever meet, they will annihilate each other in a burst of energy. In fact, that should have destroyed the universe billions of years ago, but obviously that didn’t happen. So how did matter come to dominate? What tipped the scales in its favor? Or, where did all the antimatter go?

[...] But now, researchers have designed a new method that could produce antimatter in smaller labs. While the team hasn’t built the device yet, simulations show that the principle is feasible.

The new device involves firing two powerful lasers at a plastic block, one from either side in a pincer motion. This block would be crisscrossed by tiny channels, just micrometers wide. As each laser strikes the target, it accelerates a cloud of electrons in the material and sends them shooting off – until they collide with the cloud of electrons coming the other way from the other laser.

That collision produces a lot of gamma rays and, because of the extremely narrow channels, the photons are more likely to also collide with each other. This in turn produces showers of matter and antimatter, specifically electrons and their antimatter equivalent, positrons. Finally, magnetic fields around the system focus the positrons into an antimatter beam, and accelerate it to an extremely high energy.

Journal Reference:
He, Yutong, Blackburn, Thomas G., Toncian, Toma, et al. Dominance of γ-γ electron-positron pair creation in a plasma driven by high-intensity lasers [open], Communications Physics (DOI: 10.1038/s42005-021-00636-x)


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  • (Score: 2) by PiMuNu on Wednesday August 04 2021, @10:55AM (7 children)

    by PiMuNu (3823) on Wednesday August 04 2021, @10:55AM (#1162995)

    You have antimatter (muons) travelling through you, about 1 per second. Every hospital has a PET scanner - Positron Electron Tomography. (Positrons are antimatter electrons).

    The field of particle production using plasma driven lasers is interesting - but indicating that antimatter is super exotic is wrong. Obviously getting 10^26 positrons is hard though.

    • (Score: 5, Interesting) by Immerman on Wednesday August 04 2021, @02:06PM (4 children)

      by Immerman (3985) on Wednesday August 04 2021, @02:06PM (#1163030)

      Muons are fairly exotic, but not antimatter, antimuons are. As rare as both are the classification may be a bit academic, but as you say muons are less rare, and they can coexist with normal matter (muon-catalyzed fusion is probably the most well-known application)

      As a rule, any sort of antimatter is super rare in the universe, simply because it ceases to exist as soon as it comes into contact with far more abundant "normal" matter, and the exoticness of particles is generally judged by how common they are *in nature* - we mostly know they exist because we can produce them in a lab - and if we can do that, then we can streamline the process if there's actual applications for them (such as PET)

      Probably the most interesting feature of antimatter production is the efficiency - antimatter would be an incredible energy storage medium, especially useful for things like deep space missions where the useful mass/energy ratio is incredibly important (and low-fallout super-bombs I suppose). But we need *far* more efficient ways to produce it for it to be a realistic option, since current methods are I believe far below 1% efficient. And since none of the current production methods seem to have a lot of potential for dramatic efficiency improvements, new methods are always interesting.

      • (Score: 1, Offtopic) by PiMuNu on Wednesday August 04 2021, @02:20PM (3 children)

        by PiMuNu (3823) on Wednesday August 04 2021, @02:20PM (#1163042)

        > it ceases to exist as soon as it comes into contact with far more abundant "normal" matter

        Not true. Interaction cross-section can be rather small. Antimuons being a case in point, they (usually) go straight through you and stop a few metres underground.

        > we mostly know they exist because we can produce them in a lab

        No, antimatter was first discovered in cosmic rays.

        I get it, naturally occurring antimatter is suppressed with respect to matter by 26 orders of magnitude (or whatever). But it is much more common than the article would make you think - antimatter goes through you every second.

        There's two meanings of rare - rare when compared to ducks and rare when compared to electrons. Most people, reading the article, will think antimatter is rare when compared to ducks - i.e. we never see antimatter in our normal lives, it only exists at CERN and in movies. But that isn't true. Antimatter is really very common, when compared to ducks (which I think are "common", at least where I live - I see them every day).

        • (Score: 2) by FatPhil on Thursday August 05 2021, @07:33AM (2 children)

          by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Thursday August 05 2021, @07:33AM (#1163405) Homepage
          For comparison, our intake of uranium per day is 10^-11 of our body mass, so are more than 10,000,000,000,000,000 times as common as muons passing through.

          I'll let you do the numerical comparison with neutrinos.
          --
          Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
          • (Score: 2) by PiMuNu on Thursday August 05 2021, @11:25AM (1 child)

            by PiMuNu (3823) on Thursday August 05 2021, @11:25AM (#1163438)

            Correct. Uranium is also much more common than ducks!

            • (Score: 2) by FatPhil on Thursday August 05 2021, @10:44PM

              by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Thursday August 05 2021, @10:44PM (#1163748) Homepage
              I think you're right on that particular point. Birds are low mass.
              --
              Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
    • (Score: 3, Insightful) by Beryllium Sphere (r) on Wednesday August 04 2021, @04:26PM (1 child)

      by Beryllium Sphere (r) (5062) on Wednesday August 04 2021, @04:26PM (#1163103)

      Do you have a banana in your house? Some of the potassium is potassium-40, and if I remember right one decay channel emits a positron.

      • (Score: 2) by PiMuNu on Thursday August 05 2021, @11:33AM

        by PiMuNu (3823) on Thursday August 05 2021, @11:33AM (#1163440)

        Good point!

  • (Score: 1, Funny) by Anonymous Coward on Wednesday August 04 2021, @11:05AM

    by Anonymous Coward on Wednesday August 04 2021, @11:05AM (#1162997)

    i have no laser printers in my home

    Oh, wait. Laser pincers? Well, that's the reason I stay away from the beach. You never know when Crabby McCrabface might take a shot at you!

  • (Score: 3, Funny) by Retian on Wednesday August 04 2021, @11:54AM

    by Retian (4977) on Wednesday August 04 2021, @11:54AM (#1163001)

    Laser pincers sounds like something I'd equip my minions with if I were a supervillain.

  • (Score: 0) by Anonymous Coward on Wednesday August 04 2021, @12:10PM

    by Anonymous Coward on Wednesday August 04 2021, @12:10PM (#1163005)

    Fricking laser pincers.

  • (Score: 3, Interesting) by HiThere on Wednesday August 04 2021, @01:53PM (2 children)

    by HiThere (866) Subscriber Badge on Wednesday August 04 2021, @01:53PM (#1163027) Journal

    Antimatter is more complex than just positrons.

    Positrons are useful, and we've been using them in various ways for decades (not in robot brains yet though). But they are just one component of antimatter. You need to also have at least anti-protons. You also need some anti-neutrons unless you're satisfied with anti-hydrogen. (I'm not sure you need anything else, but combining those correctly, especially the anti-neutrons, would be a real trick.)

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    • (Score: 0, Disagree) by Anonymous Coward on Wednesday August 04 2021, @04:16PM (1 child)

      by Anonymous Coward on Wednesday August 04 2021, @04:16PM (#1163094)

      Do you think electrons aren't matter? If you do, then I think you're out of touch with mainstream physics. Thus, positrons are antimatter and having them is having antimatter.

      Look at it this way. We have energy and matter. Are you saying positrons are just energy or anti-energy? I don't think the math would work out. I'm pretty sure the physics is settled. They're anti-matter.

      I think you're confused that we need to be able to synthesize anti-elements to say we have anti-matter. Atomic components are still matter. A free neutron is matter, etc.

      • (Score: 2) by FatPhil on Thursday August 05 2021, @07:39AM

        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Thursday August 05 2021, @07:39AM (#1163409) Homepage
        He's not saying they aren't antiparticles. They are simply not stable matter in our current regime. They may have been what primordial plasma was made of when the universe's temperature was measured in megakelvin, but that's not now, you need to bring yourself up to the modern age.

        Anyway, tell me more about these pions, are they matter or antimatter? Smash the matter binary - am I right, sisters!
        --
        Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
  • (Score: 2) by Beryllium Sphere (r) on Wednesday August 04 2021, @04:32PM (1 child)

    by Beryllium Sphere (r) (5062) on Wednesday August 04 2021, @04:32PM (#1163105)

    Photons colliding mean something interesting is going on.

    Classically, Maxwell's equations are linear, so adding one EM field doesn't change another.

    The paper refers to the Breit-Wheeler process, which apparently depends on quantum electrodynamics. I'd love to understand what it is about quantum mechanics that makes the photons interact so dramatically.

    • (Score: 0) by Anonymous Coward on Wednesday August 04 2021, @08:05PM

      by Anonymous Coward on Wednesday August 04 2021, @08:05PM (#1163204)

      That would be the interaction term in the Hamiltonian. You see?

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