An international team of researchers has worked out how to make a beam of positrons – the antimatter version of electrons – using lasers and a tiny block of plastic.
We have known that energy and matter are the two sides of the same coin since Einstein’s most famous equation, E=mc2. And, just how powerful light is released when matter and antimatter touch each other, it is possible to make matter-antimatter pairs using light.
However, just because something is possible doesn’t mean that it’s easy – although this new experimental setup has just shown that maybe there’s an easier way to make antimatter.
Two highly energetic lasers pulses are shot on opposite sides of a tiny block of plastic which is crisscrossed by tiny channels the size of microns. Theoretical models and simulations have backed this approach, and these findings are reported in the Nature journal Communications Physics.
"When the laser pulses penetrate the sample, each of them accelerates a cloud of extremely fast electrons,” co-author Dr Toma Toncian, from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), said in a statement. “These two electron clouds then race toward each other with full force, interacting with the laser propagating in the opposite direction.”
The collision is so violent that it produces gamma rays – the most energetic form of light – so concentrated that the gamma rays are converted into electron-positron pairs. On top of that, the setup produces strong magnetic fields which accelerate the positrons in a tight beam. The acceleration is extremely efficient – in a fraction of a millimeter, the positrons achieve energies that are usually only possible in full-scale particle accelerators.
The new method is also expected to create 100,000 more positrons than the one-laser single-treatment concept, making it more effective in terms of numbers. The lasers employed also don’t have to be extremely powerful like in other approaches, which is another advantage.
The next step is actually testing it. The team is looking at using the Extreme Light Infrastructure Nuclear Physics facility in Romania, although some preliminary tests could be conducted at the European XFEL, home of the world’s most powerful laser.
The ability to create large quantify of antimatter in such a manner might provide insights into particle physics as well as astrophysics.
“Such processes are likely to take place, among others, in the magnetosphere of pulsars, i.e. of rapidly rotating neutron stars,” added co-author and project leader Dr Alexey Arefiev, from the University of California at San Diego. “With our new concept, such phenomena could be simulated in the laboratory, at least to some extent, which would then allow us to understand them better.”
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