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Physics, Strange

How Lasers Can Summon Antimatter

Can light create antimatter? Not directly, but laser light can accelerate electrons to create gamma rays to create antimatter. If scientists use powerful laser pulses to accelerate electrons to near the speed of light, gamma rays are created. As the gamma rays collide, they create matter-antimatter pairs. Using optical traps, the electrons can be contained to create an escalating cascade.

Antimatter is an exotic material that vaporizes when it contacts regular matter. If you hit an antimatter baseball with a bat made of regular matter, it would explode in a burst of light. It is rare to find antimatter on Earth, but it is believed to exist in the furthest reaches of the universe. Amazingly, antimatter can be created out of thin air — scientists can create blasts of matter and antimatter simultaneously using light that is extremely energetic.

“Laser blasting antimatter into existence: Scientists hit trapped electrons with gamma-ray beams to generate a cascade of matter-antimatter pairs.”

ScienceDaily. ScienceDaily, 5 November 2018.

Via SciDaily

This image shows an “optical trap” for matter-antimatter plasma. The trap is formed by 4 lasers, arranged in one plane, all going towards the same point. When the lasers overlap, they form a 2D wave, with electric fields shown in the figure. There is a tiny object in the center, a nanowire 100x thinner than a human hair. The electrons are stripped off the wire and accelerated close to the speed of light. They are trapped in the wave, so when they lose most of their energy by emitting light, they get re-accelerated. The photons produce electron-positron pairs, themselves trapped. This creates a dense electron-positron plasma that eventually converts most of the available laser energy into gamma-rays.

The amount of antimatter that can be created at this stage is very small and it takes far more energy to create and contain antimatter than scientists get back from combining it with matter to make energy.

How does creation of antimatter work? This got me more interested in gamma rays. Gamma rays, unlike visuble light and x-rays, cannot be caputred and reflected by mirrors because gamma-ray wavelengths are so short that they can pass between the atoms in the mirror surface.

If we could see gamma rays, the night sky would look strange and unfamiliar. The familiar view of constantly shining constellations would be replaced by ever-changing bursts of high-energy gamma radiation that last fractions of a second to minutes, popping like cosmic flashbulbs, momentarily dominating the gamma-ray sky and then fading.

Via NASA

According to an article on futurism.com, if you could see gamma rays, you could see and avoid radiation on earth.

If you could see gamma-rays, you’d see black holes and other super energetic events (if you were in space) and radioactive materials on Earth.

Via Futurism

Gamma rays are also created in lightning.

On Earth, gamma rays are produced by nuclear reactors, lightning and the decay of radioactive elements.

Via Symmetry

If gamma rays are created during lightning, from all we’ve read above we can guess that antimatter may form from lightning as well. Indeed, beams of antimatter have been detected in earthly thunderstorms.

Scientists using NASA’s Fermi Gamma-ray Space Telescope have detected beams of antimatter produced above thunderstorms on Earth, a phenomenon never seen before.

Via NASA

Beams of antimatter? Yes, there are beams of positive electrons just as our more familiar negative electrons can form beams.

Did you know that hurricanes launch beams of antimatter at the earth? Downward beams of positrons, the antimatter counterpart of an electron are also detected in the eye of hurricanes.

In addition to positrons, another type of antimatter, antiprotons have been created in a lab. The idea of using antimatter to power space ships is still being explored.

Antiprotons can be used in propulsion to produce direct thrust, energize a propellant, or heat a solid core.  The simplestconcept uses antiprotons to heat a sold metal core, usually tungsten.  The tungsten absorbs the gamma rays and pions from the antimatter/matter annihilation and is heated.  Small holes are placed in the cylinder containing the core where hydrogen gas can enter.  As the hydrogen gas enters, the tungsten core is cooled while the hydrogen gas is heated.  The hydrogen propellant is then expanded through a nozzle to produce thrust

Via utexas

If you want to make antimatter in your garage, here are some technical details you should understand about how antimatter is created before proceeding. This is an answer to my earlier question, how does antimatter creation work.

A high-energy electron, when it comes near a nucleus, will feel the electric field of the charged nucleus, and be deflected in its path. The larger the charge of the nucleus, the more frequently this deflection will happen at large angles. When a fast electron is diverted from its straight-line path, it radiates some of its energy away as photons. High-energy photons, when they come near another nucleus, can spontaneously turn into an electron-positron pair (conserving charge and the “number of electrons”, which both add to zero since a positron has positive charge and is an anti-electron). The second nucleus is there to exchange energy and momentum with, otherwise you cannot start with a photon (zero mass) and end up with two objects with mass and conserve energy and momentum. 

If the electron and positron thus produced have enough energy, they can undergo scattering with more nuclei, radiate photons which can pair-produce more electrons and positrons, creating a whole “shower” of electrons, positrons, and photons. Positrons then can be separated away with magnets and collected in particle accelerators. 

Via Illinois.edu

Make sense? You would need plenty of lead shielding. Gamma rays can be deadly or can lead to radiation induced cancer.

A good start might be to build a Penning trap.

As for positron, antiproton and electron plasmas: a Penning trap will certainly do the trick. In a Penning trap, charged plasmas are confined in a superposition of magnetic and electric fields.

Via Cern

Hans Dehmelt built the first Penning trap and shared a Nobel prize in Physics in 1989 for this technique to trap ions.

Getting back to the original idea in this article, before known success in creating antimatter using lasers, this was written:

A key concept behind the team’s work is based on the quantum electrodynamics (QED) prediction that “a strong  can, generally speaking, ‘boil the vacuum,’ which is full of ‘virtual particles,’ such as electron-positron pairs,” explained Igor Kostyukov of IAP RAS. “The field can convert these types of particles from a virtual state, in which the particles aren’t directly observable, to a real one.”

One impressive manifestation of this type of QED phenomenon is a self-sustained laser-driven QED cascade, which is a grand challenge yet to be observed in a laboratory.

Via Physics.org (2016)

If this all leaves you with many unanswered questions, you are not alone.

Bored genius club adjourned, for now.

TrueStrange.com

About Xeno

E pluribus unum.

Discussion

2 thoughts on “How Lasers Can Summon Antimatter

  1. So we are already making quarks and electrons out of nothing… is there a way to turn the antimatter into normal matter?

    Liked by 1 person

    Posted by Chris | 22 Nov 2018, 10:40 am

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