[MUSIC PLAYING]
Hi, thanks for that talk.
That was really, really, really interesting.
I know at the LHC, there's been a blip at 750 GV.
Do you have any idea what that might be?
It might be supersymmetry?
So interestingly, so I should point out,
because I work on accelerators, I'm
not part of that particular collaboration.
So I'm not-- but I do have a background in particle physics
and I went to a seminar on that the other day.
So I can tell you categorically that they
don't know what it is.
[LAUGHING]
Yet.
In fact, they don't know-- the thing
is about the statistics of particle physics
is blips can seem to appear.
And then when you get more data, they can seem to disappear.
So this is an exciting one at the moment
because it has almost kind of something like three sigma
significance.
If you've been following, three sigma is kind of always a hint,
five sigma is discovery, champagne.
So it's not quite at the significance level
that we need yet.
So really there, we're waiting for more data.
And that should actually be released,
those results, within the next few weeks I think actually.
So watch the news for that.
It might disappear though.
But let's hope something else crops up in its place.
Yeah, John do you want to add to that, maybe?
Or ask something else?
[INTERPOSING VOICES]
He's the expert to ask.
[INTERPOSING VOICES]
No, no.
I don't know anymore, you said it very well.
No, entirely different, it was a wonderful talk.
Thank you.
And I'm not an expert on accelerators,
I just get the data.
So it was really good to see how they work.
Now I also am aware of people from the high energy physics
community investing in plasma wakefield
technologies, not only for high energy actually but also
further applications.
I just wondered if you had any comments on that?
Do you think it's a runner?
Should we be worrying more about that or is it interesting?
Worrying, no.
Supporting, yes.
So plasma wakefield acceleration is
a sort of relatively new concept where
you generate a plasma, a much higher temperature
than this one.
And inside a plasma, the electrons and the ions
are already broken down so it can't spark.
And so that can give you a very, very high gradient accelerating
field.
Now at the moment, the status of that field
and those experiments is that they
can generate very, very high gradient but only over a very,
very tiny distance.
So their not reaching massive energies,
they're pretty reasonable for the tabletop
size of the experiment.
In terms of applications, some of the things
that they will create will be useful for applications,
especially at the sort of low energy level.
But the beams they create at the moment to an accelerator
physicist-- [INAUDIBLE] not going to mind if I say rubbish.
They have a very large spread of energy, they're very messy,
they're very unpredictable, they're very irreproducible.
Shot to shot there's quite a difference.
That doesn't mean they're not going
to be really useful for something application-wise.
It may mean that you could figure out
how to put different sections after each other
to drive up to very, very high energies
and learn to control that.
In my particular field of high intensity,
it's not something at the moment that we
can conceive of being a competitor to a more
conventional type of accelerator.
But while we're opening up the field
of different applications, there's
certainly a place for having very compact sources that
perhaps could go on the back of a truck
or out into the field to widen the applicability
of the machines.
Thanks.
There's a gentleman there in the white with a red tie.
Just wait for the microphone.
Jane, he's just there.
Is it this gentleman?
I'm a med chemist.
Can you explain to me one thing that's puzzling me?
In terms of medical applications,
specifically to treatment of cancer.
Yeah.
A proton is, what, 1,837 times as heavy as an electron.
Does that mean that a proton beam has a disadvantage because
of the much higher momentum of damaging surrounding
non-cancerous cells compared with an electron
beam or beta rays?
How does it actually stand in terms of medical applications--
proton versus electron.
So quite the opposite, it has quite a neat advantage.
You're lucky my PhD was designing
a machine for proton therapy, so this is very much my area.
So protons, when they go into the body, go into water,
they have a very different interaction
with-- as they go through, compared to say x-rays.
So if x-rays go in, they deposit most of their dose on their way
in, and then they're dose rate falls off as it goes deeper
into the body.
And the same is actually true of electrons because they're light
and they interact easily.
The protons are heavier, they have higher energy.
They don't interact as easily.
So they go in and they don't deposit much energy,
say something like 20% of the dose.
But then the great thing about protons
is they actually slow down towards the end of their range.
And that dose level goes up and you create this peak of dose
at the very end of the proton range.
And then the protons stop.
And we call this shape the Bragg peak.
And it's a very well understood description
in physics of how that works.
So proton beams, you can actually deliver a higher dose
more accurately, further into the body
without damaging surrounding tissue.
And in order to tune the depth of that peak
and where it lands, you just have
to change the energy of the incoming beam.
And these machines are something like-- to get
about 25 centimeters, which is the range of most people's
bodies, it requires about 250 Mega electron Volt protons.
So the slight downside is it requires
a much larger accelerator than conventional radiotherapy.
But it is a standard technique now.
Proton therapy has treated more than 115,000 patients
around the world.
And the NHS are currently building two full body proton
therapy centers in the UK.
They're particularly good for childhood cases of cancer,
where you don't want additional dose in the body
because that can induce later effects later in their life.
And it's particularly good for very deep
seated and hard to reach cancers.
So we will be getting that before long.
And that's something that also we're
trying to develop the technology to shrink down the size
and cost of those accelerators and improve the treatment
outcome as well.
Thank you.
Nice question.
Can resonances be controlled by using dampening devices
and so reduce the spread of a mix of particles in a beam?
Thank you.
Yes.
Brilliant question.
Yeah, that's kind of the next step, isn't it?
So these resonances, I kind of only
introduced a sort of basic form of them.
But they can actually happen in many different dimensions
with many different interactions and there
are many different so-called instabilities
that can build up at different points in the acceleration
cycle.
Some of those we can damp with oscillators.
So we measure the oscillations.
We have a very fast feedback system.
And then some kind of dampening system tuned to that in order
to damp it back down again.
The ones in the main beam with that spread of tunes
that I was talking about, unfortunately if you damp one,
you'll drive another.
So that makes it slightly more difficult.
But yes, in principle we are thinking
more about how to use, say, high frequency dampening
systems to do that.
But some of those take a long time as well.
So that's-- if you're trying to accelerate a beam very quickly,
many cycles a second, that can get in the way as well.
So great question, thank you.
Marcia, is there anyone up in the gallery?
Because I always forget.
No?
There's one up there.
Or there's a question over here.
Cheeky in the front, here.
A few months ago, we had a lecture on fusion reactors.
And the gentleman there was saying that on ITER they
had modified the field so it doesn't
hit the outside of the toroid by having a helical field going
around the outside.
And I'm wondering whether the things you are doing
has any applications to fusion reactors?
Yes.
So we can't contain our beam in quite the same way
because it's a much higher energy beam
and it's much more precise.
But interestingly, on the other end of that,
there is one very important application
of high intensity accelerators related to fusion energy.
In fact, it's vital for fusion energy
because as these fusion reactors operate,
they get a huge amount of radiation
into the walls of the vessel despite it being contained.
There's a lot of radiation hitting the side
of the wall of those vessels.
And that causes a lot of defamation and destruction
of the material that we don't understand very well
at the moment because we've literally never had
a device that spat that many-- that much radiation of that
form at those kinds of materials.
So there's a facility being developed
called the-- it's IFMIF.
It's the International Fusion Materials Irradiation Facility.
Yes!
And that's actually going to take quite a low energy.
It's much, much lower energy than the ones
I was talking about even, but even higher intensity
of deuterons usually, because that simulates the radiation
they're getting off.
And that's such a challenging accelerator to build.
They're actually building-- their current project
is to build a prototype to even prove that they could build
the accelerator to do that.
So then they can create a materials and radiation
facility to try and understand how the materials in a fusion
reactor are going to behave when they're actually
in the real deal.
So that itself is an ongoing project.
Because it's low energy, they face
slightly different challenges from the ones
that we do up at the slightly higher energies.
But yeah, it's a vital thing for them
to figure out how to do this stuff
is to also potentially realize fusion energy.
Yeah.
So I think this is going to be the last question.
With the catastrophic political shift that we've had
[INAUDIBLE], I've got to bring it up.
This is clearly a very collaborative field
of research.
What's going to happen in the future?
So, yeah, it is a very collaborative
and very international field both in Europe
and all around the world.
So I can't speak for the future of something like CERN.
CERN is a political organization,
the UK is a member state, so I don't
think that will be affected.
However, in the sciences generally,
a lot of our funding, about 10% of the UK science funding
comes from the EU at the moment.
And so that is likely to have a large impact.
My institute-- I think, some of our major projects
are European funded.
In the short term, of course, we're
told those will continue to be funded no problem.
But in the future, you know, it could seriously
impact the progress and especially the UK's standing.
We lead a lot of these projects at the moment,
and we may not be able to in the future.
So I was hoping rather to get to the end of your discourse,
maybe without that kind of question.
Someone had to throw it in.
An opportune moment to actually start clapping again
and [? recognize ?] Susie's fantastic discourse.
Thank you for so much for explaining.
[APPLAUSE]
Thank you very much.