Keeping it safe
We have to stop it annihilating
To use antimatter in medicine or engineering, we need to be able to store and transport it. But as soon as we create even a single positron, it will annihilate with an electron in the matter around it. The only way to stop antimatter annihilating is to keep it away from matter.
We can store positrons in a positron trap: a vacuum tube with strong electric and magnetic fields.
The electric and magnetic fields hold the positrons in the centre of the tube, so they can’t come into contact with the sides of the tube.
The vacuum in the tube stops the positrons coming into contact with the air.
This is one of our positron traps. It’s about 30cm long. Here at the Centre for Antimatter-Matter Studies, we normally use this type of positron trap to store a few million positrons at a time, but it could hold as many as a billion.
Not perfect, but good enough
The vacuum in a positron trap isn’t perfect: there’s always a small amount of air left in the tube, so every now and then one of the positrons in the trap will meet an electron in the air, and annihilate. Eventually all the positrons in a trap will have annihilated, so the antimatter will be lost, but positron traps can store antimatter for long enough to be useful.
Now that we can store antiparticles, can we put them together to build up anti-atoms?