Name: 物理学実験の解剖学-60の記号 (Anatomy of a Physics Experiment - Sixty Symbols)
Uploaded: 2021-01-14T10:29:07.000Z
Duration: 12 min 31 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

程度の副詞

We are at the [diamond] [light] source just outside Oxford in England

[we're] here for the next week or so [to] do an experiment and we are standing in the synchrotron right now

Think that [one] is a particle accelerator

Where electrons are circulated around put in a roughly circular or a pretty well circular trajectory?

Very very very close to the speed of light. We are not so much interested on like Particle physicists

We're not so much interested in the particles of themselves what we are interested in for our

experiments is the fact that when you take a charged particle like an electron and

Circulate it very very close to the speed [of] light or accelerate it very close to speed of light

What's called synchrotron radiation. So this is radiation that goes all the way from infrared up to very very hard very very [high-energy]

X-Rays and we as condensed Matter physicists solid-state physicist nano scientists

Whatever you want to call us what we are most interested in is harnessing that light

Shining it onto a sample and learning about what the atoms and molecules

And that sample are doing we walk around is there's a sort of hissing noise

And the hissing noise comes from nitrogen gas now because of this very bright light that we have it's very very focused

But it can get quite hot so we are standing right above. What is called Beamline eyes zero name

What's a beam line? Well? You have the electrons circulating around. How do you get the light out well?

through which the light travels and also as you can see

Us going off into the distance you might be able to see this in terms of just coming off

We're on the surfaces and interfaces line just here just down here and we will be collecting that light

Coming from those electrons and shining it onto our sample down in this experimental hatch down here

So to get beam time you have to like anything in science

you have to write a grant proposal you have to get the time you have to get the funding for the work and

We wrote that proposal quite some time ago almost a year ago now

So we were hugely excited when we got the time and they were hugely excited to be here to actually be able to exploit this

So what we're looking at here is obviously we need to have optics to get this light down

But this isn't optics these are X-Ray optics

And we need to be able to get those x-rays onto our sample to focus them down the synchrotron is about 10

So this is an immense engineering challenge with very very clever people doing this work

To ensure that we can get that those very bright x-Rays and get them on to our sample

Coming down here is actually the tube that is carrying the beam [to] [our] to our chamber, and it's also a high vacuum

So it's a pressure comparable to that you get on the surface of the moon the electrons are not [allowed] to the electrons are basically

Circulating away over there what [we're] what is coming down

This Tube is the light generated by those electrons, and that's going to come into or similarly ultra high vacuum chamber

We're going to have those x-rays and they're going to impinge on our sample

And then we're going to find out wonderful things about our particular molecule

This is where we actually do the experiments and the light actually comes in through this Tube here

And then we're going to chase out through the tumors ETc some more optics some

Diagnosis, and then we're coming all along all along

Into our experimental chamber here. It's an ultra high vacuum Chamber [Stainless-steel]

Pressure in here very very low again comparable to the surface of the moon and our sample sits in there

So the beam is coming into our chamber, and it's going to the beam is going to hit our sample

And it's going to eject the electrons out and we want to measure the energies at which those electrons come out

It's actually something called the photoelectric effect which it wasn't for a relativity that Einstein won. His nobel prize

It was actually for the photoelectric effect something called photon emission

that's what we're doing here one part just one part of what we're doing here photons in, electrons out and

Every material has [its] own signature in terms of its photo emission spectrum, so this is our electron energy analyzer this wonderful

and it's literally called a hemispherical analyzer and

The way we measured the energies [of] the electrons is that we have a couple of spheres in here, and we put a voltage on

those spheres and then what we do is we [clear] off the

Force on the electrons against that that voltage so we play off the centripetal force against the electrostatic force and

only those electrons that I've got the right and

Kinetic energy the right speed are actually going to make it through and then we vary the voltages and we can collect a spectrum that

Precisely, that's exactly what it does. It's an energy pencil. So it it allows us to detect how many electrons

We've got of a certain energy all these different arms

It's also allowing us to move samples around in vacuum without

Breaking the vacuum and so we can use these arms to move the sample around

What they're doing over here? What Sam's doing at the moment is sorting out?

The the important aspects that this experiment [let] me tell you about the experiment

We're going to do so this is the [molecule] were interested, and it's a absolutely fascinating molecule

It's a [C60] it's [a] what's called a Buckminsterfullerene

We've got a single water molecule, and this is made. We don't make this we're not half clever enough

We are physicist  we are not clever enough to do this. This is made by our colleagues in Southampton

They do something called molecular surgery they open up a hole in the cage

they drop a water molecule in and then they seal up the hole just with wet chemistry it's

Phenomenal the water molecule is trapped within the kids. It's in kids its incarcerated within within this molecule

Why is that interesting [well] first of all you've got a single water molecule not interacting with any other water molecules

[this] is not something you find very often in nature the C60 is about a nanometer across once you confine

Molecules once you confine atoms and once you confine particles to small spaces

That's when you start to see very interesting quantum effects

What we're really interested [in] is can we exploit those effects when we take this molecule and put it down onto a surface

And the first question to ask is when you put it down onto a surface and the cage bonds to the surface does the molecule

Inside does the water molecule feel the effect of the surface

Or is this just like a faraday cage does it completely screen it out

So that [the] water molecule doesn't see the surface there are a number of different things

We do both up the first is to exploit this photoelectric effect this photo emission effect photons come in

We excite electrons out [of] the oxygen and we can look at the spectrum [of] those

Electrons to work out, what's happening with the water molecule? Where do we get those photons?

Well we get them from the [beamline] why do we need the beamline and why is a synchrotron?

Why don't we just do this with an X-Ray source back in Nottingham?

Why don't we do [it] in a lab the great thing about a synchrotron?

across a very wide range in this case from hundred Electron volts of the killer Electron volts that's a

Remarkable tool because we can tune in on [particular] parts of the spectrum and work out what's going on the challenge of this experiment?

it's a really fun experiment to do is we take a silver surface which everybody is busily preparing at the moment and

We're going to put our molecules down onto that surface the first challenge is how do we get the molecules down into the surface?

well what we do fortunately would [C60] we can take it as a powder, and that's how we

guess we get about a milligram of these molecules at the black powder we put it into an oven it's literally an oven and

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物理学実験の解剖学-60の記号 (Anatomy of a Physics Experiment - Sixty Symbols)

literally

absolutely

technique

fascinating