If people meet me at parties they normally ask me what I do,
and I say I'm a researcher.
I'm a scientist.
And if I said I was a physicist people would sort of slowly back away...
Hi, my name is Suzie and I design particle accelerators.
A particle accelerator is a machine designed to take either atoms, with the electrons stripped
off,
what we call ions, or the particles inside the atoms themselves,
so electrons or protons, and give them energy,
increase their speed.
The main way is using electric fields to accelerate and magnetic fields to bend and control the
particles.
So the earth has a magnetic field and coming from the sun is charged particles
The only reason those charged particles don't irradiate us is because the Earth's magnetic
field uses exactly the same principle and bends them away from us
and actually protects us, almost like a magnetic shield around the Earth.
So that same principle, in physics that's called the Lorentz force.
A charged particle in a magnetic field gets bent, so we're using exactly the same principle,
but to bend particles around in an accelerator.
And if you take an electric field, an electric potential,
and you sit a charged particle within that, it will feel the electrical force which will
move it from one side to the other:
like charges repel and opposite charges attract.
We literally just use that basic principle to give a particle a small kick or push,
and if you do that enough times over and over
it gains more and more energy.
I think there is a creative process that people go through when they design accelerators.
Often the design of an accelerator starts with one person and their concept.
Most particle accelerators really do have a recipe.
So there's 5 ingredients: the particles, where you get those from, how you make them.
There's giving it energy, there's some sort of acceleration mechanism,
there's control, so that's usually the magnet system, how you control and organise the beam
of particles,
there's collision, which not all accelerators are colliders as in beam-on-beam colliders,
but we usually use the beam for something.
So we usually collide it with a fixed target, or even into a person's body, or just onto
some kind of sample or screen.
And then there's detection.
There's no point doing all of that
unless you can actually measure what's going on with the beam at the end of the day.
There are lots of different types of particle accelerators,
but we can classify them into three main categories.
The first one is a linear accelerator.
As the name suggests, it's a straight line.
Most commonly they're used for radiotherapy in hospitals to accelerate electrons,
and using those generate x-rays, and then the x-rays are used for cancer treatment.
The other two types of accelerators are circular.
Probably the most common one, in terms of numbers, is called a cyclotron.
It's a compact, relatively old-style accelerator in which the particles start in the centre
and as they gain energy they spiral outwards.
To reach higher energies, we use a machine called a synchrotron.
A synchrotron has to keep both the electric and magnetic fields perfectly synchronised
with the particles as they increase in energy.
That's where it gets its name from.
We have two big synchrotrons on site at the Rutherford Appleton lab.
One is the ISIS Neutron and Muon Source, and the other is the Diamond Light Source.
The Large Hadron Collider, the world's biggest accelerator, is also a synchrotron.
I spent 3 months working at CERN as an undergraduate student.
The first time I went out there this thing was so big, and so complex.
I was an ant in an ant hill.
I just thought, 'this thing is never gonna work'.
And yet, they switched the Large Hadron Collider on and it worked as smoothly as I've ever
seen any accelerator start up.
It's an incredible machine and an incredible team of people.
usually they're such long term projects that in some accelerator control rooms,
if you go in there there's a series of corks or empty bottles
that have written on them 'first beam' or 'first user cycle'.
When you reach a major milestone, the bottle of champagne is quite a ubiquitous thing in
my field.
We don't drink much champagne, but we do like to rack a bottle when 20 years later you get
the beam on.