Question: what is a particle accelerator?

Hayley Smith answered on 15 Nov 2011:

Ah, a particle accelerator is an awesome machine!

What they do is they take charged particles and make them go really really fast

OK, so the charged particle, what could that be? Well, atoms are made of two types of charged particles – protons and electrons. We’re not considering the neutral neutron here. But there are other types of charged particle we can talk about too, think about atoms that have extra electrons or protons, such as H- (Hydrogen with an extra electron) or Pb+ (Lead with an extra proton).

So how do we make these charged particles go really fast? How do we accelerate them? There’s a few special properties of charged particles that we can tap into:

Charged particles will be accelerated by an electric field. So if I put a charged particle between two electrodes (a negative cathode and a positve anode) then the charged particle will be attracted or repelled, depending on it’s charge. This is due to Coulomb’s law, like charges will repel, opposite charges will attract.

Also, charged particles can be deflected in magnetic fields. This means that if you have a charged particle whizzing along and you put a magnetic field around it the particle will change direction. Using different kinds of magnets it’s also possible to squish and squeeze your beam of charged particles into different shapes – kind of nifty!

So…Particle accelerators simply use a combination of electric and magnetic fields to move and speed up charged particles – it’s great!

Once you’ve got your charged particle up to speed you can do whatever you want with it!

Where I work, we accelerate protons and then smash them into a target so other scientists can use what comes out.

At CERN, in Switzerland, they accelerate two lots of protons really really really fast and then smash the protons into each other, they then look at what comes out in some really complicated detectors.

Medical accelerators would accelerate charged particles and then use them to treat cancer tumours as it is easy to control the energy of the particle. The particl energy needs to be altered depending on how far inside different tissues a tumour may be.

Hopefully that’s answered your question, but if it’s not (or there’s things you don’t get or want to know more about), comment back and I’ll try to explain it a bit better…!
Thanks
Hayley