Question: How frequently do you encounter antimatter and how long can you isolate it? (if thets what you do)

David Freeborn answered on 17 Jun 2013:

At the LHC we make lots and lots of antimatter in every single collision.

Whenever very high energy particles meet, they usually make a shower of new particles. For each particle that’s made, we need to create a corresponding anti-particle too. So, we end up with quite a lot of it.

In fact, we’ve started using small particle accelerators in medicine, to make anti-electrons, called positrons. We use the positrons to scan organs in the body- a technique called “positron emission topography” or PET scans. The positrons collide with particles in the human body, and we analyse the radiation given off.

Storing positrons for any length of time is really difficult though. We can try to do it using a “magnetic cage”- by placing magnets in the right way, we can trap a particle in their magnetic fields. We’ve been able to use this to store an entire anti-atom for 1000 seconds- about 17 minutes. It’s still very hard to store antimatter for longer, but the techniques are getting better all the time.