Original subtitles

The cosmos,

and all of its galaxies of stars and planets,

are part of an intricate design, shaped by something

that's been eluding scientists for decades.

The hunt for dark matter is going on worldwide.

We haven't been able to see it.

It's invisible to us.

We're not sure exactly what dark matter is at all.

We have built massive machines

on top of mountains.

Our laboratory is the observatory.

And below Earth's surface to explore.

It takes imagination.

Imagining what that dark matter might actually be,

and then design a detector, design an experiment around it.

And now, a technology way ahead

of our current capabilities brings us to the point

of greater understanding.

If we can interact with it fundamentally,

this is really important to our understanding

of where we are in the universe.

A dramatic advancement in the hunt for dark matter

has begun.

We're trying to piece something together

that's very hard to see, because it's dark matter.

There's a good chance it's made up of particles,

these particles were produced in the very beginning

of the universe, in the Big Bang,

and they've been around ever since.

Somehow my gut feeling tells me

there are particles out there we can detect.

Scientists describe two phenomena

that emerge at the time of the Big Bang,

dark energy, the force that has caused the universe

to expand for about 14 billion years,

and then dark matter, the substance that has provided

structure to everything within it.

Both are deep mysteries yet to be proven.

Because dark matter is so elusive,

scientists are attempting many different experiments

to find it.

One experiment involves trying to create

particles of dark matter.

As soon as we know we can make it,

we can design machines to study it.

Joe Incandela and his colleagues

at the University of California at Santa Barbara

are part of a multi-national effort to create new technology

that is unimaginable in scale.

The technology they're building is a particle detector

called the High Granularity Calorimeter, or HGC.

The High Granularity Calorimeter

is a six million pixel camera,

it has to be capable of taking images every 25 nanoseconds,

for anyone who's, you know, played with cameras,

knows that this is utterly insane,

this is the highest resolution slow motion camera

anyone's really kinda built.

They're essentially building a detector

that's like a camera that can record and process

10 terabytes of data per second.

That's something like a 1000 word essay

by every human being on the planet every second

in terms of amount of data.

Our electronics engineer pointed out,

this is more than the entire internet worldwide

we'll be producing in 2018.

The HGC will have 22,000 silicon wafers.

It will eventually capture 2400 times the data per second

over the existing detector,

increasing the odds of finding dark matter.

The task that was given directly

were to manufacture some of the first generations

of what we call the module PCB.

PCB stands for printed circuit board.

This is the basic component of the HGC,

which is multilayered in its construction.

On the underside here, we'll have a silicon wafer

that'll come in and sit under the PCB.

And wire bonds will go from the top surface,

from each one of these small golden dots,

down to the PCB underneath,

and that will be how we host

the two major important components,

that's the sensor and the front-end electronics on top.

Designing the HGC began with an idea,

but it did not come with a set of schematics

on how to build it.

It was like, here's a sack of parts,

and those parts need to fit this space,

and you gotta play Tetris 'til it works.

Believe it or not, probably the thing that's

giving us the most trouble

is finding space to get the cables out of the detector.

There's very limited space.

When you build a big detector like we have at the LHC,

you don't want cracks.

You don't want places where particles could not be detected.

So you design these things to be very hermetic,

very well sealed.

That means there's very few places cables can go,

and the spacing for the cables is very tight,

and so that's actually a big problem for us.

The team at UC Santa Barbara is collaborating

with a team at CERN, the European Organization

for Nuclear Research located in Switzerland.

CERN houses the largest high energy physics experiments

in the world.

The target for the High Granularity Calorimeter

is the Compact Muon Solenoid Detector, or CMS.

This 15,000 ton science experiment,

buried 30 stories below ground,

helped find the Higgs-Boson in 2012.

At the moment, in our experiment at CMS,

we have devices now in that region that

at each side is a 10,000 pixel camera.

We're gonna replace those sides

with three million pixels each,

and we're gonna design a device that will actually

allow us to have capabilities we've never had before.

This increased resolution will allow scientists

to see billions more particles produced

by the Large Hadron Collider,

making it harder for dark matter to hide.

Jim Strait is a particle physicist

who's part of a team to integrate the new technology

into CMS in the hunt for dark matter.

My big job is to help coordinate

the overall technical design of the new Endcap Calorimeter.

The Endcap Calorimeter is a key component

for finding evidence of dark matter.

The detector of course can be opened like an accordion,

into the various slices, which allows us to get

at the existing Endcap Calorimeter.

What we have to do is make a new calorimeter

that fits into exactly the same spot.

I would say that the detector we're building now

is an order of magnitude more difficult

than any detector we've built before.

Not necessarily in terms of what the basic components are

that go into it, but in the way it's built,

and the compactness of this device

is different from anything we've ever done before.

Overall, the biggest challenge in this

is figuring out how to get the signals out.

We're building the device that has

six or seven million channels,

and you have to bring in power and other signals

that control how the detector works,

all inside the same space that is already there,

without compromising the performance density

and coverage of the detector itself.

Experimental physics on this scale

is a result of another branch of science,

observational astronomy.

It is astronomers who figured out the presence

of dark matter in the first place.

There's two reasons why we believe dark matter

is important and exists.

Firstly, we feel its presence from its gravity,

so the motions of galaxies and clusters of galaxies.

We know that those motions are governed by

something that's very very massive that we can't see.

Secondly, gravitational lensing,

the bending of light by massive objects,

enables us to chart how much dark matter there is

and also where it is.

Astronomers like Richard Ellis

search for visible proof that dark matter exists,

in this case, on a mountain top on the island of Hawaii.

The romance of going to all these remote mountain tops,

building these wonderful machines,

is an example of something our civilization

does supremely well.

At nearly 14,000 feet above sea level,

the dormant Mauna Kea volcano on the big island of Hawaii

is home to some of the largest telescopes on Earth.

Just think, every night when you go to sleep,

there are dozens of astronomers all over the world

beginning to work, making their observations.

Astronomers have a variety of telescopes

for looking at dark matter.

We're here at the Keck Observatory,

this is an optical ground-based telescope.

We have a partnership basically

with the Hubble Space Telescope,

particularly in the area of gravitational lensing.

So what you're seeing in this image, at a stroke,

is the tremendous power of gravitation lensing.

A huge foreground cluster with lots of dark matter

is distorting and magnifying large numbers

of background galaxies as various distances.

But then you can see this red arc here

that is very very nicely illustrated,

it's about three times further away than the cluster.

And you see there are multiple images,

you see the same light of the galaxy,

the distant galaxy, seen in different places.

So it's like a mirage.

So this opened up the way of studying dark matter

thanks to Hubble.

While the Hubble Space Telescope

can gather extraordinary detail from space,

ground based telescopes provide a bigger picture.

Dr. Ellis uses the Keck telescopes

to measure the distances between Earth

and the galaxies themselves,

to interpret the influence of dark matter

on the structure of the universe.

What we're trying to do is provide

those key distance measurements

through analyzing the light of these background galaxies.

This 300 ton telescope, with a 10 meter mirror,

is being positioned for tonight's work

to look into the stars.

Dr. Ellis and two students are in communication

with the technician.

Okay.

We're setting everything up here

for tonight's observations, and you know,

fingers crossed we're gonna get great data.

You could say dark matter is something of an embarrassment,

you know, first detected in the 1930s.

We are told often that we live in the golden age

of astronomy, and yet here we are 80 years later

and we don't know what it is.

Because it's 85 percent of the known matter

in the universe, and 95 percent of the universe

is not known to us.

For an experimental physicist, that's a pretty bad record.

We've spent centuries.

We have this incredibly detailed understanding,

but it's only of five percent.

One, two, three, four...

There's four pixels.

It's like four pixels.

In the blue as well.

That's amazing.

The idea of discovering the nature of dark matter

is funding effectively very big advances in instruments,

both in physics and in astronomy.

All of these are driven by the mystery

of trying to solve the fundamental question

of what is dark matter, why is it there,

and why is it so important in understanding

the history of the universe?

Fritz Zwicky, a scientist

from the California Institute of Technology,

came up with evidence for dark matter in 1938

while studying a galaxy 20 million light years away.

He concluded it could not have formed into a spiral

without additional gravitational support.

But it wasn't taken seriously until nearly 40 years later

when two scientists from Carnegie Institution,

Vera Ruben and W. Kent Ford,

did measurements of spiral galaxies

that led to the conclusion that dark matter was essential

to the structure of the universe.

Finding it means we can begin to confirm

centuries of theories, but even more,

discover new ones we could not before imagine.

The High Granularity Calorimeter is a big technological leap

toward reaching this goal.

It will be a huge task to mass produce

the thousands of elements that make up the entire system.

UCSB is responsible for establishing the methodology

for building them.

To basically set it up.

Establish the kind of tools that are needed,

all the procedures, the equipment,

establish how to do this,

and then we will transfer that capability

to four or five centers worldwide

that will do most of the production.

We specifically are working developing

an automated assembly process for the sensors

that will go in the HGCal.

The HGC is a huge huge project.

We're gonna be making 22,000 sensors.

This silicon-based sensor

has an intricate design to capture particles.

Its six million detector elements

will be linked via microscopic connections.

This is a pattern we have taken a lot of time to develop.

You'll notice that there are many circles,

each one of these circles will surround

one of the openings on the PCB.

Once assembly has been completed on a robotic gantry,

we bring it over to the wire bonder.

The wire bonder will make the actual bonds

from the sensor to the PCB,

and from the PCB to the onboard electronics

which digitize the signals that are created

from the particles passing through the silicon.

Once I get it, I have to attach wire bonds

between the silicon layer and the PCB.

We take 25 micron aluminum wire

and we use ultrasonic energy,

and it kind of vibrates the two materials,

and it kind of fuses them together

so that we can have talking

between the silicon and the chip.

It's really, really thin,

and it's wound around either a half-inch

or a two-inch spool, and we have to use a microscope

to lead it through each of the wedges,

and that takes a lot of practice and a lot of frustration.

Once we write the program and set it up,

then we can send it off and nobody else has to do that,

so we go through the hard labor and then

let them just use our program.

But before the High Granularity Calorimeter

goes into full production,

the teams have to make sure it works.

Testing at CERN provides an optimal high energy environment

to create dark matter particles.

Dark matter is going to be very interesting research,

because by definition, dark matter is different

from the usual matter.

It doesn't interact.

Not interacting means it's invisible

On the other hand, if it gets produced, and it flies out,

it's going to carry with it energy.

If dark matter is made up of particles,

then the Large Hadron Collider can produce it.

The collaborative work to build and design the HGC

includes testing under high radiation conditions.

Dave Barney is a physicist and project manager at CERN.

He is responsible for the testing.

This hole we're in is one of a couple of facilities

at CERN that are almost exclusively for testing prototypes.

The beam starts in Switzerland,

with a bottle of hydrogen gas,

which is stripped of its electrons

and you just get left with protons.

Then they go into a circular accelerator,

and then another circular accelerator.

So the main one we use, called the SPS,

Super Proton Synchrotron,

is in itself an extremely powerful device.

Now this makes the protons go extremely fast,

very close to the speed of light.

When those protons reach top speed,

they're actually extracted and they're sent down a tube

and they hit a target,

and a spray of other particles comes off of that.

Electrons, other protons, particles called muons, pyons.

And then send those ones down this line

into our experiment.

We've always been kind of pushing the boundaries

of what is capable in electronics technology

and detector technology.

This device needs to survive at -30 degrees Celsius

in a massive radiation environment

for 15 years, with no maintenance.

The radiation comes from CERN's

Large Hadron Collider.

It has a system of superconducting magnets

that guides particles around its 17 mile system

at near the speed of light.

When a particle travels through it,

the detector generates some sort of signal

that then electronics amplifies and stores, if necessary.

So we're testing, at the moment,

eight of these in a beam here at CERN,

we've tested up to 16 of these

in a beam at Fermilab in the US,

and we're trying to understand

whether they perform as they should.

This module is actually composed of several layers,

starting from a plate that sits on top of this copper plate

that supports the whole thing.

And then it has the silicon, and then it has

the printed circuit board on top of that.

And they're all glued to each other.

Our prototype is based on

these hexagonal silicon sensors

that are divided up into smaller hexagons.

Mostly, there are some funny shapes around the edges,

but they're mostly smaller hexagons.

So each of these smaller hexagons

is an individual particle detector, if you like.

And we're testing some of these in a beam at the moment.

The conditions at this beam line area

are similar to conditions within

the Compact Muon Solanoid Detector.

This is a critical phase in the development of the HGC.

The stakes are high, because this project will take

eight years and cost millions of dollars to complete.

To find those elusive few things

that might be really interesting,

we need an unprecedented precision of our detectors

to disentangle between the boring stuff,

the stuff we know about already,

and the really interesting new stuff.

That's where this sort of detector comes in.

As predicted, the High Granularity Calorimeter

is proving to be a great success,

capturing particles in a wide distribution of energy ranges,

moving us closer to unlocking

the deep mysteries of the universe.

Dark matter is something that

really takes us to the next step.

And so it'll be a wild moment.

No doubt about it.

Most of what we were doing so far

was to check that we had a working concept,

make sure we weren't going down the wrong road.

We've already collected data on

a stack of 16 modules at Fermilab,

a stack of eight modules at CERN

to test some of the absorbers

and get some of the first statistics back already.

This detector has incredible capabilities.

It's also extremely challenging to design and build,

and to handle all that data.

But if we can get it all to work,

this will be, I think somewhat revolutionary for the field.

When the 22,000 silicon wafers are completed

for the HGC, they will reveal particle showers

in greater detail than ever before,

and maybe through this we will find dark matter.

If we find it or don't find it,

it has an impact on our understanding

of particles in general.

We think it has to be particulate, it has to be out there,

it has to have some interaction with our universe,

if we can't make that connection,

we have to go back to the drawing board

and try to understand what it is

and how the universe was formed.