Plus thirty days.

You're right it's

the day in Georgia that
I just masters physics.

Or just getting

somewhere else and here I just research

never ever says where he is now
a reasonable research site and

you're right if you like the optical
electro optical systems.

And it is also from director Michael
like from that you know well and

he's working group which
is one of the situations.

Senator I know.

So today he's going to
talk about something.

Thank you so just quit show and

how many people were forced to come
here because it's a large crowd.

You know I figured as much as thank you.

I'm going to discuss some of the work
we've been doing and making simulators for

radiation detection and the approach
we've been using instead of creating.

What are standard similar
materials which are single crystal

materials of some compound.

We've been trying to engineer
the Cinelerra compounds.

Using nano particles
in a composite matrix.

So I'll give a little
background about simulators

background my quantum dots for you.

For those of you who know about them.

I apologize but.

I'll go through that quickly and
then particles and

then we'll talk about
composites in polymers and

composites in glass I'll summarize and
this work has a variety of support

over the last few years from N.S.F.
the N.D.O. Oakridge National Lab.

We've had pure students work on this as.

He's had some funding from German and
he's OK So

simulators and our particular application
for simulators Guimaraes spectroscopy.

And I'll get more into
that as we go along here.

But Gary spectroscopy is
used in safety security

scientific in medical applications.

So we're converting gamma
rays into the light.

That is detectable by photo detectors that
we're taking some high energy particle in

Korea to lower energy that we can
deal with the manage and detect.

So from a game or
a spectroscopy point of view each game or

a has a characteristic energy.

Depending upon its supply where it comes
from I'm sure you're familiar with X.

rays that come from different.

Atoms and different shells in the electron
shells there's a specific energy

that you can use to identify
the element it comes from.

Spectroscopy we take that energy
which is convert to light and

we take that light output and we light
output is proportionally intense to

the energy is employed conservation of
energy more energy in more light out.

So we have a game where you come in
it converts to a pulse of light and

we count that pulse of light
we see how high it is and

we put it in an energy been and
that keeps gives us an energy spectrum

profile then that we can used identify
the most isotope of identification and

that's important to minimize false
alarms and screening carbon Tanner's For

example if you have a carbon taint or
full of cat litter.

It's radioactive cargo container
full of bananas it's radioactive.

So you can imagine shipping port
a cargo container comes in.

Someone walks around with one of these.

Geiger counter.

And says this thing is radioactive.

This thing is radioactive we better
shut down the port and get in or.

Yellow suits and we go in and we find out.

Scott later.

I'm sure you've been in hotels
where the fire alarm goes off at

four in the morning.

Nothing's happened you fire alarm
goes at five in the morning.

Nothing's happening.

You back to room next time the fire alarm
goes off what happened here nor it right.

Too many false positive.

You start Inori.

The detection.

In fact I hear that some of the machines
at the airports they choose not to use

of the ones they give a lot of false
positives this by the way is some

Georgia beach sand.

So.

I'm not sure where it's from but

I probably would stay away
from that particular beach.

And.

OK So what are the requirements for

gamma ray spectroscopy so
gamma ray is a high energy quanta.

So to interact with that we'd like to
have material that has the highs e and

a full density we offer Miller that
lead is a good absorber of radiation.

That's because it's very dense all
the atoms are close together and

it's a high C.

There's a lot of I don't like trunk shells
there to interact with the gamma ray.

Because we're converting
gamma rays to light.

We want.

This material to create light
efficiency efficiently.

So one of the metrics is how
many photons you get out per And

we make electron volt of
energy of gamma radiation and

once you make that light you have to get
it out of your simulator very efficiently.

Because if you can't collect it
outside of your material it's useless.

And only must get out easily.

So you must have a transparent
material and look.

Must get out uniformally
to the photodetector.

And this is.

Combine.

This is a photo multiplier Tube for
detector.

This is actually a one inch
simulator crystal on top here.

And this is just the base
that connects this.

So the foetid checked or as you should
generally on one side of the Senate.

Crystal.

So if I create light one
wherever I create light

in a similar Crystal I want to transport
that efficiently to for a multiplier.

And the reason is if I have
one game where he comes in.

It gives me a certain light pulse heights.

Because it's got a certain energy of
gamma ray for another game or it comes

in the same energy but you don't collect
all the light from the light pulse.

Suddenly it appears that you have
a different energy of gamma ray coming in.

So you like to get this
uniform lice light pulse

distribution out that you can get
high resolution spectroscopy.

Now if you're in a very hot zone where
radiation is coming in very quickly

you're similar have to respond
quickly enough to be reset for

the next quanta of radiation coming in.

So you'd like to have high speed response
on these on these simulators and

of course we like to have a good spectral
match we want the wavelength of light

coming out from the simulator to
match our photo detector typical

photodetector is high sensitivity
our photo multiplier tubes.

They generally peak in
the near ultraviolet for

the standard type of photo cathodes so.

Right now good using PM ts a good spectral
match is near ultraviolet or blue.

OK So this is.

Example of this is my simulator
material here in this case

I'm talking about composite now but.

That's why these particles here I have
a gamma ray come in and converts that

the light like goes out into my detector
which is called the multiplier.

I collect those light pulses the pulse
light spectrum then you get so

basically this is a beginning
of the light pulse spectra So

what you get is each of these corresponds
to a different type of light pulse.

When you some of those all up.

You end up getting peaks that correspond

to a particular isotope and
what's important.

If I see.

Lucian wise if I have if I miss a little
bit a light in one of those palaces.

Then my peaches up in for here.

So I end up broadening the spectrum.

The broader the scats suddenly these two
peaks and no longer individual peaks they

overlap and now you have difficulty
identifying I said So ideally you want.

Very good light a collection of fish and
light because statistics increase the more

light you have and that gives you better
resolution and of course there's.

If you characterize your similar material
properties software things you can use

to do to give you better
resolution than intrinsically

you obtain from the material.

OK so the current simulators are really
halide materials single crystal.

So to my diet is the work or standard.

Lanthanum bromide Syrian
is a newer material.

Unfortunately it's subject to a patent so
there is really

a French company that supplies this
they can charge an arm and a leg for it.

Strontium I dyed your opium is a new
type of material that's being developed.

But they are all their issues and
one of those issues.

Is that they all melt
when exposed humidity.

So you have to make the single crystal
in a large single crystal material.

Furnace.

You have to do it inert atmosphere.

You have to cut it up in an atmosphere and
you have to hermetically seal it

in a thing before you can
use it in environment.

Also because there are these here
like crystals are very fragile.

You know probably if I went digging on
that it would crack through the Cleeve

through the material.

So it's essentially a salt crystal that

will start melting when
exposure to humidity.

So what that does the fact that I have
to seal this in some sort of enclosure

now precludes me from
measuring the lower energy

gamma rays because my encapsulation
which has to be environmentally robust.

You know it's OK on your your.

X. P.S. system inside a vacuum where
you can have a thin X. ray window but

when you're using these out in the real
world outside of a laboratory instrument.

They have to be able to be
more mechanically sound.

The other type of quanta radiated
particles one of those alpha particles.

Alpha particles the mean free path and
there are a few centimeters.

So literally even with
a tiger type counter

you have to be within a couple
centimeters of the material detected.

So there's no way it's getting through any
kind of thickness of material like this.

So if you want to do gamma rays you
need to have your Similary be exposed

to the environment.

I'm sorry alpha particles need to have
a similar that can be exposed environment

without any kind of encapsulation.

And I will point out that.

Polonium is a strong
alpha particle matter.

And if you recall a few years
ago there was a K.G.B. ex K.G.B.

agent in the United Kingdom who
was poisoned with polonium.

Because you can't detect it
unless you're right next to it.

There is some put in his food and
those alpha materials tend

to replace the calcium in your bones
calcium comes out the radiation goes in.

So you seen pictures of
people's people handling

Spears of plutonium right and plutonium
is a strong alpha particle matter but

in fact the fact that they have gloves on
protects them from that alpha particle.

But if it gets into mainly and makes your
body alpha particles emit say four M.

Evie particles.

There's light energy it's getting
dumped in the immediate surroundings.

So I think I've said
this single crystals and

the other thing is you know you
have to do a lot of development

to make these single crystals
each single crystal material.

Requires a lot of development just for
that one and to do the large size.

If you want to have
a large detection volume.

Even more so.

OK So I think I've said enough.

There.

OK So the approach here is to replace

sealing crystals with engineering
composites signaling that of particles.

So what are the potential advantages here

ease of preparation compared to
growing large single crystals.

So now we're talking about making
you know a powder of something.

Let's say or
a cloying census in a pot or in a flask.

That's a lot simpler then doing this.

Having to develop the single crystal.

Processing technology for
they have lives and

that allows me to look at
a lot of different materials.

Because now I'm a composite.

You know I have to have a furnace
this big to go Christmas big but

I'm talking about plastics.

You know I can have my.

Nanoparticles there.

I stick them in some polymer and
I politicize this and now I can make you

know a very large thing in a plastic
I can make it out plastic I can make.

Interesting shapes out of it.

It's hard to do with Crystal.

So I can make something that fits
in a particular location in plastic

even I can even bed the detector
element so instead of having.

Photodetector a one in here.

I can start thinking about embedding.

Inexpensive photodiodes
everywhere to collect the light.

An entire volume.

So there's a lot of potential for
making these materials cost.

Certainly this is much
cheaper than doing the.

Once we make of course much cheaper
than doing the single crystal materials.

And now because I don't have to deal
with the single crystal uniqueness of

every single crystal.

I have a lot more choices of
materials I can interrogate.

Things that don't emit light and also so

we're going to nano particles
were also can be changing the.

Optical properties material.

So I'm sure we can take non light emitting
silicon we make quantum dots out silicon

certainly a light emitting so I can now
do materials that would work as a bulk

material and possibly use them as and
then a composites I can look at Hi-Z.

materials lead materials etc.

And the other important point is
remember I need a transparent composite.

So if I only have a few nano
particles in here I'm not going to

have much interaction my game or a So
I want to put as many in here as possible.

But because those are dissimilar
materials from my matrix.

I refractive index difference.

And I'm a cause light scattering.

So Glass is transparent
until he grind it up and

you have light scattering from all the air
glass in our faces but once the particles

get small enough they stop interacting so
strongly scattering with light.

Like think of it if you have
a ocean wave coming in.

You have a beach ball in the ocean
wave there's not much interaction but

once you get something the size of
an ocean wave like an ocean liner.

Then there is interaction so
by minimizing these size these

particles I can put a lot of material in
here and still maintain transparency.

So just to show that
here is some modeling of

scattering a nanoparticle there is in this
case the matrix is a polymer one point

five the nanoparticle Foster material
has an index of two point four So

there's a very large refractive
index different in this case.

And what you see is the mean free path
that's the the pathway can travel between

before being scattered by
another nanoparticle and

this is fifty percent volume loading so

half the material by volume is not
the polymer it's something else.

And you see the as you go to smaller size
particles the mean free path goes up and

the earthing as the wavelength gets
larger the mean free back goes up so

that the difference between
the size of the part.

On the wavelength
the light is what you want.

And of course you would still like to
match the refractive index is much

possible because that's
also reduces scouting.

But it shows that you can do
quite a bit of material and

this is ten centimeters I mean free path.

So you can make very large
things with now particles and

still have them be transparent.

So technical pro church
was to put together for.

Nanoparticles.

Lighting there are particles and

quantum dot missions sources highly
loaded those make transparence.

Simulators Index Match as much as we
can and we put this in glass matrix.

So we looked a lot of different materials.

As you can see here not small on compound
but typically binary materials or

turn area of this and we looked on
liquids because I actually don't you know

if you can have a container to hold liquid
in you can use that as an letter as well.

I mean it brings up some other issues but
it can work.

And we have also looked at besides
conduct's we've looked at nano

particles the headlight basin and
of particles.

Many different things.

Again and liquids polymers and glasses.

So what is a quantum dot.

Well.

It's a very small particle and I'm sure
as you're all well aware as we start

squeezing things down quantum Well one
day you can Vironment quantum wire to D.

as we get to a three D. confinement
zero dimensionality particle point.

We really start squeezing
electron wave functions in there.

And once the particle gets down to about
the sides of the bore radius that's

the extent of the electron.

X. ton wave function as we start
localising the electrons are all members.

EISENBERG uncertainty principle if
you know electron is you know that.

As.

Time's position must be
equal to some number.

So if you start having knowing
your lecture on is in the energies

got to go up.

So this is what's happening here.

So with YOU THINK ABOUT A You
have a bucket of water and

the energy levels the surface the water
you start squeezing the bucket in

that water level goes
up the energy goes up.

So I have a now a means of tuning.

By just changing the size of
the material the emission wavelength.

So now I can possibly I could take
a material that would be useless and

infrared material but
that infrared material as high as Z..

Components and and
I can move that into the U.V.

region of the visible where I can
now use standard photo textures.

The other thing that happens is
this localization as you are.

Localizing your electron and whole wave
functions you're overlapping this function

so now you create it a more efficient
optical transfer process because now

they're localized and
they can interact with each other.

Faster.

So you can change the wavelength
you increase the efficiency and

you can make materials that are not
light emitters like matter.

The sense of this process for
these is really conceptually very simple.

This is happens to be cadmium
teller I'd say you have cadmium ion

solutions you inject Scroope
six precursor to Laurie.

That interacts with the cadmium and

precipitate out cadmium
telluride particles.

What you have to do in this
process is important is to control

the growth because they need to be nano So
if they grow too big.

Suddenly they're not nano anymore.

The other thing is that if two particles
come together to nano particles now

become the nano particles.

So you lose your properties.

So typically what you do is you put
organic Liggins on the outside here that

keep these two from coming together.

And this also these organic
Liggins also slow the reaction

processes to a reasonable time
where you can control it.

The reaction process is by
limiting how fast your.

Your eye on can get into reacting surface.

So you can control the process and create.

So you what you'd like to do in
this process is nuclear first and

then grow so you don't want.

Once you have a series
of particles in there.

You don't want to create more nano
particles because you like to have

a a uniform particle size distribution so
you start nucleation and

then you just go below the concentrations
that you have no more nucleation and

you just growing shells on the outside.

You know particles.

And basically by as we
said getting smaller.

We go to higher energy so we can go from
take an infrared material calving teller

I'd move it into the visible smaller
quantum dots which are the ones you make

first are the higher energy ones.

So this is what typical
emission spectra look like.

These Gaussian Specter for quantum dots
as you go smaller particles shift it.

And there is also a shift in absorption so

basically quantum dots absorb pretty much
everything higher energy than they are.

So you'll see.

Typically the emission Specter
is just to the right of this X.

town absorption peak here.

So I mean tell it's great.

As I said photo Mopar tubes
are typically operate in the near U.V.

or blue silicon however can
operate out to about one micron So

if you get silicon for a multiplier solid
state for multipliers then we can take

advantage of going to longer wavelengths
remember longer wavelengths scatter less.

So if we operate a longer wavelength.

We have longer mean free path.

And we can then maybe get in the sweet
spot for a silicon fighters actor and also

a lot of the highs the materials like the
LEDs and the mercury's tend to be in for

a materials anyway so we can move those
in and these are just examples of.

These are murky.

Tell her I quantum dots.

And you see.

This is coming tell adversus
Mercury tell ride and

you see visible mission infrared emission.

So I have I can change to my properties by
size and I can change them by materials.

So I have a couple knobs to turn.

And.

If for some reason you want to you can
move these out into the Midway via our So

these are examples these are led.

Or these are led solenoids of different
size you can see short wave on and

out into the Midway via our emission.

So the other applications for
these things of course.

OK so I said we have to
mix these quantum dots and

composites and we've done this in
a number of different polymers

this happens to be poly
methyl my fact relate P.M.A..

We've made sizes up to this large size.

But.

So now remember.

If my particles clump together then
they suddenly become not so Nano and

I get enhanced scattering I'm going to
pass around some of these composites.

So when I'm curing.

And this material is curing
something large like this.

It doesn't cure uniformly It doesn't
cure from the inside out it cures

from the outside in and
you get segregation

forces pushing the limits and so I have
a number of these little things here.

So if you look in the center of there
what you see over the course of actually

months.

These materials actually
even the bags actually.

Put.

Just look in the center of the light or

actually caused a higher concentration
of quantum dots in the center.

And you can see that if
you can look up like.

So the other thing about quantum dots.

It is they absorb a lot
of their own light.

So this shows the overlap.

I had two separate charts for
now I've put them together.

This shows the overlap of the mission and
the absorption.

So when you have a very large structure
like the one that's going around.

You'll actually see that it's a quantum
dot emits light it doesn't get to the air

side because of absorbing
its own emission.

So that's a problem.

So mixing is a problem and
the self absorption problem.

So we can start with.

So we've got to keep them thin so
we have thin composites

the curing is no longer an issue
self-absorption comes less issue so

here's here's an application for
that in X. ray imaging.

So these are quantum dot.

Composites and it's just showing that.

This is now comparing to a standard X.
ray screen which is made of gallium

oxy sulfide terbium that is a powder
screen it's large particles.

There's a lot of scattering So
if you want to high resolution images

from a spatial point of view you like
to have something as transparent and

it's not scattering light
to different locations.

So this just shows if we use
this quantum dot we actually get

five lines per millimeter
resolution compared to the standard

two point eight that you get with.

The standard screens.

OK so you can play tricks however to
move the absorption and emission away.

So before we were relying on the intrinsic
properties of quantum dot to emit light.

Now we put impurity in the open or an
activator that actually gives the Stokes

shifts so now here's the absorption
of these quantum dots and typically

the climbed out within minutes right
here but by putting this active area I.

And in that emits light.

I've been able to shift the emission
away from the absorption be.

So now I have another knob I can tune or
turn.

I got size I got material now
I got impurities I can put in.

And one of the interesting things
about when you do these dope and

is that the emissions stability comes
very stable at high temperatures.

So when the applications of
the game are spectroscopy

is actually an oil well drilling or in.

Geothermal drilling.

So as they're drilling through the earth.

They're actually looking at the Emery
specter they have neutron sources except

for a They're trying to see what they're
drilling through what the material is so

they know is this where I'm
going to get my oil etc etc.

But it's high temperature
under the earth course.

So this is an application
where such things work.

One of the problems they have with that is
they use these standard simulators a story

my time here which I told you is temps are
offensive and environmentally unstable.

They're using those down below now and

they desperately would like
something else they could use their.

Interesting aside on
that if you think about

you know many tens of
thousands of feet of drill.

Do you ever and they have electronics
on the bottom the drill Do you ever

wonder how they get signals back and
forth.

It's interesting they
actually have a generator and

Obama drill is providing power but if you
recall they pump water down the drill and

they basically use they pressurize
that they pulse that pumping water and

that gives them communication back and

forth through something that's
turning ten thousand feet away.

OK.

So quantum dots.

They have this problem.

The poem or zation that we
talked about has this problem.

Maybe some solutions there and
they can be used in some situations.

So quantum dots are but there are small
enough to get a quantum regime

while we can also have nano particles
which are small but they're not yet.

In the quantum regime for
that particular material.

So now we're talking about
making other materials now.

I still even if it's the same
materials as the simulators

here which are more sensitive
I can handle this more easily.

When I'm making powders than when I'm
trying to grow a large crystal so

I can have access to those materials and
other materials.

So this is an example of a chemical
synthesis of let them fluoride Syria.

And this happens from X.

ray Spector happens to be nine
man an enemy or particles.

And this emits right around
three fifteen I mean this is

the extension specter
of this is the mission.

And this is a crude bed here I don't know
if you can see it very well but this

vet has fifty percent of that material
is nano particles other than water and

saps who transparent.

So that's the beauty of nano particles.

OK so.

By volume.

Yeah.

So however.

I'm going to be putting this in a poxy or

a polymer that may absorb that U.V.
light so maybe we look at other lights.

I'm sorry absorb that wavelength light so

maybe you look at other materials we
shift to a little better wavelength.

This happens to be barren fluoride Syria.

And so that case now we're going to have
less ultraviolet direction by the poxy

matrix so it was more options and
what we're putting together.

And just like quantum dots.

I have my base material in this case we're
talking about lamp implied Syrian so

I have to put in activator in order.

I can put an actuator in but I can also
use a CO activator to take that U.V.

material and now shifted to the green so

same material I lub it terbium and
I've created a green emitter again.

Fifty percent material in here.

Of lanthanum fluoride serum terbium and
this is actually very similar to the.

Position of the green lighting the
material that's in your fluorescent lamps.

They in that case the Syrian absorbs U.V.

very fission Leon transfers energy to
the visible that we use for light.

OK.

So typically we worked with the poxy.

When we made these and they are composite.

And even those are nanoparticles
remember the barren fluoride ones

where I didn't point out but they were
forty nine years a little bit larger.

You can see that.

If I don't do some index matching.

This is transmission through my.

Through my cylinder composite I actually
do get very large scattering So

it's still important to do that as much
as possible depending upon the side.

Size of the material and see the.

In the water.

It's a cloister Lucian's the particles
are separated very nicely.

Again with the composites
Now you're mixing stuff.

Did you mix it did you get
uniformly distributed or

is some forces causing alarm aeration.

So we're only really able to get
in the poxy is up to about ten

percent loading before it
started become scattering.

So the problem here is that my normal
similar crystals are one hundred percent

loading right so if I took that material
ground it up into nanoparticles and

put it here ten percent loading then my
thing needs to be ten times the volume to

have the same cross-section
absorption cross-section

that the hundred percent similar Matilda.

So that's the drawback of the and
then a composite approach.

So obviously you want to
load as highly as possible.

Now of course if you have the space.

It's transparent.

It's cheaper then it will work for you.

OK So these are some gamma rays spectra
of pain from the anthem fluoride and

barium fluoride Syrian.

So.
What I show here is channel number which

is equivalent to energy in this
scale number of accumulative counts

in the energy and what you see this is
exposed Amery simply have a radiation

coming lab in our laboratory that we
have all the various radio nuclei and

so we can do this type of.

Measurement.

This is Emory's him.

Which is.

Pretty much the standard radio nuclei
that's in your smoke detector.

So you can go buy a smoke detector
rip it apart and you have Emory.

Emory's emits a fifty nine collect volt X.
ray and

also alpha particles they use the alpha
particles in the smoke detector.

But it's a fairly weak X. ray.

So that's why they allow you to have
it in your house without a license.

So what you basically see is
you get some sort of peak here.

That corresponds to the X. ray.

Now it's not a very good peak.

You know you look at these you say.

Which one is my X.
ray here is this the position and

it all depends upon its combination of
interaction and getting the light out.

So this one peak height has a stronger
interaction higher loading but

it's less transparent so you get less
light out so the pulses are reduced and so

that's what ships are here.

So this shows a proof of principle but
it's not terribly useful in that format.

OK.

So part of the problems of
using the quantum dots and

then a part of the polymer is the mixing
is you getting them distribute uniformly

in a liquid it actually works pretty well
but force that offers other difficulties.

So.

We investigate a glass ramming approach in
this case the nano particles are created

in situ in the glass and while we're
creating last we create the new particles.

So the main parts there's
no mixing after the fact.

Once they're in the glass.

We can.

So we limit the mix the limit the need
to mix the glass and impart those.

And because you're you can do more for

your sense materials because they're It
instantly sealed in the Hermetic glass.

In fact glass is used the ceiling for
radioactive waste over Savannah River.

Plant down here in Savannah.

That's what they used to
store waste long term.

So it's a nice composite material.

The other once once I get the nail
particles in I can treat them afterwards I

can and Neil them below the melting
point to make them larger So

now I have a knob I can turn to
change the size and then particles.

But what happens in the glass.

It's essentially
a precipitation mechanism.

I know if anyone made rock candy
when they were kids sugar solution.

You'd warm it up and
you'd put more sugar in

them could be in their water at room
temperature you let it cool down.

And you nuclei in
the sugar precipitate out.

So that's what we're doing
here we have a glass.

We put a similar component in we super
saturated but high temperature is fine but

as soon as it cools down it
precipitates the nanoparticles out.

And the kind of neat thing about this.

The Fusion length of
those ions in the glass.

You know it's glass the solidifying
there's very short diffusion Lang So

as the particles precipitating it can
only sample a small volume around it and

so what that does means that
the particle size is limited so

I now have small particles and I get
a nice uniform distribution as particles

to me on a uniform mixed begin with.

So it's kind of a self limiting mechanism.

It does it in situ.

And it makes our job a lot
easier to some extent.

So these are some examples and
I forgot to light up my stuff.

These are some examples of
glass ceramic composites.

Typically we looked at sodium
alumina Borosilicate glasses and

we've looked at taillight materials.

You know in the M L Lodz calcium elides.

And we don't those with rare earth
serum terbium and your opium.

So this is a serious material this is
terribly material which emits green.

This is your opium three plus which
emits red that wouldn't be good for

food to multipliers.

But the searing material
which emits in the near U.V.

very blue is nicely tune to
standard football player tubes.

And I'm sorry I forgot to.

While you with these things but so.

These are the quantum
dots here you can see.

Very nice.

This is yes our.

Quantum dots are nice luminescent.

This is infrared quantum dots.

It's black because it's
absorbing all visible light.

Of course if you could see this with
infrared camera that be blinding you.

In fact even in root just just
the light from here will excite it so

you see it in for a camera.

And we're talking about our.

So far this is one of our composite and
you can you can sort of see there that.

The light emission intensity is dropping
off as you come up the top here because

both of self-absorption and
the strong absorption of the radiation.

So these are some of our glass
materials again much more robust than

the the single crystal materials
I think it's so these are all.

Blue one.

My favorite ones are Swan We
made that really.

And I have some other green ones in
here but so those are materials we made.

And people have done glass remix for
years.

There is actually there is actually
a serious glass neutron detector.

But the issue is a lot of these
things give light out but

you remember the specter I showed you.

They weren't very good spectra so you get
a light signal but you don't get spectra.

So prior knowledge the glass remix
we made of the first time that

anyone's ever been able to capture game
respect are using this type of material.

So as I said you know it's pretty
straightforward from conceptual point

of view you mix the materials together.

Some of these materials lower the melting
point so you don't have to go so hot.

But typically we're talking in the About
a thousand the grease was materials would

melt it homogenized and we pour it as
a poor as it's solidifying and this is.

The particular piece we made
with the neck coming off and

just by pouring it we create and
particles.

After the fact.

Now I go back in and Neil this sample and

grows nanoparticles larger you know
time temperature type profile.

I can grow so
large that the crystals get so

large that the composite becomes no longer
transparent you can see large growth.

You know micron sized grains in there.

OK So this is T.M.
analysis of some of these materials.

So you kind of get this
homogeneously distributed and then

a particles This is a close up showing
the crystal nature of the particles.

In the gum fluoride.

OK so some optical characterization.

This is a serious dope material.

So the Syrian has two
emission peaks depending upon

the material it's in the matrix it in it
actually can become one broad peak and

that's what you see happening between
these two in the gallon fluoride in

gallon bromide and these are the emission
of the absorption peaks and

there's very little overlap between
the absorption and the emission here.

So you have very little self absorption.

OK talk about the decay
time being poured in.

If you want to do a high
rate measurements.

Or if you're doing some sort of
coincidence where you have two things

happening want you will be able
to time them to say this is.

Not a noise there's some relation vents
one part comes in it splits off in the two

particles going opposite directions so you
can have two detectors and you can detect

those time intensely and say it's not
a noise it's an actual detection event.

So having a fast decay time is good Syrian

is a great element as it has the Cape
Times on the order of sixteen in a second.

And this just shows some of
the kicker is for these materials.

OK so getting to the crux of the matter in
terms of spectroscopy this is now Specter

our simulator this happens to be something
about that they supposed to bury in

one thirty three sodium twenty two and
cesium one thirty seven source and this is

the Spector obtained from the standard
sodium are dyed single crystal detector.

So what we see here is now we
have very well resolved peaks.

I can look at this.

This is barium this is
sodium this is cesium.

Once I calibrate my system of course.

What you will notice is we're still not
as good resolution as the sodium I die.

So what are what are our limiting
effects Well we're doing glass coring.

We're not really a glass.

Lab So as we're pouring in those
little bubbles that show up in here.

So you get some light
scattering from that.

OK So we do some mixing while
reporting to get the but

why were melting at the bubbles out.

As we poor you get in.

Can't you think a syrah become you get
a layer in a layer so you get some some

non-uniformity in cooling so
you get some gradations in fact of index.

So you can see a little
bit of waviness in there.

So those are things that
are engineering things.

That can be worked out.

With the appropriate Quitman and
people and certainly it.

This is not all the realm of
the glass manufacturer of Corning or

shot to make this.

And so you know your glass whiteboard can.

Become a radiation detector or.

You know you put this in a vehicle.

That you have an infrared absorber
with enough conversion so say.

You know you think about
a Humvee in military and

someone's targeting with an infrared
laser and suddenly you can see the spot.

You're Winchell because it turns green or
the infrared laser is going there.

So incorporating these type of nano
particles in glass is not a large stretch

and once it gets into manufacturing
it should be fairly straightforward.

I should point out that when I say.

We have the same gammy sorry gamma ray.

Carrier.

As a study my DI detector.

That means.

For the same volume we're able to absorb
the same amount of gamma ray as these so

you might die detector so we have
the same cross-section there expect.

We don't have quite the resolution or

the light output that the Sony My
diet has so that work needs to be on.

This point you could think cheap detector
a Detect glass detector in every light

post you know out along the street so you
crowdsource these things instead of having

one really good sector you have a lot of
inexpensive not quite as good detectors.

And because they're environmentally
sound you know you can put them up

there without worrying about them.

And so you can see a lot of
applications where the sheep.

Put in your cell phone etc etc.

Now.

We're talking about gamma ray but
and I told you so

to my died because you know because
these things are covered with.

Environmental shielding they can't detect.

Alpha particles.

We can now detect alpha particles because
we don't need a shielding our device and

this is example of a recent source
which I mention has alpha particles and

gamma rays.

Here's the gamer a peak.

Here's the alpha particle so

now we can use one material to do
two different types of actions.

And if we put lithium in there now.

The Team Six or

Boron now we can make it sensitive
to neutrons so here is a spectra.

Of material exposed to
a California source.

Which emits neutrons.

Of course we have to put a polymer
material to thermal eyes neutrons

we put that plastic around it.

You see we're able to check neutrons now.

And also we can actually detect.

In the material some of the.

Fission products of this
cesium one thirty seven.

So we can actually detect the cesium
impurity in the material as well as

the neutrons It's amazing.

So now one material you can make it kind
of more of a universal detector material.

OK So various nano particles
quantum that's been since

size we model try to modify them
to change the absorption and

mission properties dispersing these in
the polymers works OK but not great.

More work.

We need to do in that to get better for
larger elements.

Maybe an additive manufacturing
instead of doing it is one thing but

really interesting Lee in this we've
been able to create some glass

remix that are actually able to do for
the first time gamma ray spectroscopy.

So thank you very much.

I just have one more
point to show this is.

This is this is not a particle
is very highly doped or

loaded water again if you
can see it very transparent.

So these particles.

You saw there's a broad emission this
particle this is yeah it was presume it

actually has narrow line emissions and
those lines.

Some of those lines
are affected by temperature and

some were not so if you can
measure the spectrum of this you

can actually measure temperature
by taking a ratio of two peaks.

So the application for this.

Was to look at the temperature
inside of a jet engine.

So these are so small colloidal spent.

They say suspended in jet fuel.

They're small enough they
go through the filters and

they go through the injectors
inside the engine so

if you have a a port of you port
in the engine you can actually.

So you have to use a laser to
excite it you flash a laser and

you take a picture and you see actually
the distribution of the injector.

And then also if you
take two cameras with two

filters on to look at two
different wavelengths.

Now you get the temperature
distribution as well.

The flow distribution.

So a lot of neat things you
can do with nanoparticles.

In that respect.

And that's it.

Thank you very much.

There

it is.

So this

this just has kind of room temperature
issues the polymers are used for

the two hundred degrees C. temperature.

I would use the classroom mix.

Your question.

Those are about

fifty to seventy percent
loading by weight.

Around me so.

We've used processing to incorporate
quantum dots in two glasses.

So we're relying on
a super saturation here.

I don't know how I don't I mean the melt

technique is the most
straightforward method.

The.

We have of course is only
certain materials work right.

They have to be somewhat soluble
tempura But then on some level.

So we're a little bit more limited
in the materials we can do.

Yes.

So

have nanoparticles some real application.

Yes absolutely.

The.

The light filters on your stop
lights are nanoparticles.

The red lens on your stop lights is
a nanoparticle composite course.

I mean you talk about new stuff or
just in general.

Well.

We have actually had someone
license this technology so.

So far we've generated a few hundred
dollars in revenue but they're working on

that Georgia Tech's you made more for
us but but.

Yes so so
serious a lot of applications medical.

People or so you have nano particles
Now you can functionalize them to tag.

Antibodies.

You know and so
I think that's a very really

hot medical is obviously a hot area and
then of particles in medical So

gold in a park or gold in a particles
you have them functional and

a body which then you inject it sticks
to tumor and then you put some R.F.

in the gold there and particles it will
be our feet up and kill only the tumor.

But I mean there are there
are through the years.

There are many.

You know more mundane applications and
then of particles that were accidental.

Or you know they didn't really consider
themselves nanoparticle it was just

they were mixing things and
getting it to operate.

But there are certain lot of
patents out there on it and

hopefully will continue to develop
this and get some more applications.

Other I mean certainly.

Other things we're working on or.

Creating.

X. ray screens imaging screens for.

Cancer treatments where you have.

Six to ten M. e v X. rays bombarding
a person a typical screen and

you want you want to read be able to
see you know millimeter sized tumor.

So a scattering screen doesn't
give you much space or resolution.

Also the typical.

Power screens are not robust so
you have to replace them.

So this is something that would
go underneath the patient table.

You know what the began from there was so
we're actually working on creating.

Something this big the glass to give us
the glass because it's transparent gives

us a very good spatial resolution and

because robust You don't have
to change it out so often.

Well.

So it's a question of how well
they're coupled in the lattice so.

So yes.

Yes yes so

that you see the Syrian emission that is
very broad means it's got good coupling to

lattice because there's a lot of phonons
spreading out so that one actually.

Another application is not just
the well the ratio is nice

because you don't need any calibration.

Just take a ratio doesn't matter
the intensity drops by a factor of two

on your signal but
the serious ones actually.

You can just there's
temps are questioning so

once you get above a certain temperature
you get this quenching And so

you can actually use that as
a temperature measurement as well.

You know.