Download Science Theatre Nuclear Physics and FRIB Show INTRO – 4 people

Science Theatre Nuclear Physics and FRIB Show
INTRO –
4 people – Host, Businesslike, Cynic, Enthusiastic
Have the cosmic ray detector out, flashing or beeping or whatever it does…possibly
covered so it can be pulled out or unveiled or whatever.
Host: Hi everyone and welcome to the Nuclear Physics and FRIB Show. We’re a group
of students from Michigan State University’s Science Theatre who have been working for
the past semester to put together a show for you about the FRIB accelerator, and the
science it will be designed to study. Feel free to ask questions at any time!
Lets begin with introductions. (Have everyone introduce themselves, name, year, major,
etc.)
Businesslike: FRIB stands for the “Facility for Rare Isotope Beams.” In December 2008,
the US Department of Energy awarded MSU over five hundred million dollars to build it,
and when it is completed, it will be a world leader in rare isotope research!
(Pause)
Cynic: Sorry, I know you’re all excited, but so what?
Businesslike: It will be a world leader in rare isotope research!
Cynic: Yeah, okay, but what does that mean? And why should I care?
Host: Calm down guys, let each other talk, there’s plenty of show to go around…What
are you doing? (to Enthusiastic)
Enthusiastic: I can help here. Ta da! (unveils cosmic ray detector…enthusiastically)
(the others stare for a second)
Cynic: And what is that thing?
Enthusiastic: This, my friends, is a cosmic ray detector. It detects cosmic rays, which
are actually particles with very high energies which bombard the earth from space,
moving at nearly the speed of light. 10,000 of them pass through (a square meter) your
body every second, but we can observe them using special detectors, like this one.
Cynic: Wha—
Enthusiastic: Let me guess: You were going to ask, what does this have to do with
FRIB and nuclear physics?
Cynic: No…yes.
Enthusiastic: I was hoping you’d ask. You see, it is thought that many of the particles
which make up cosmic rays are spewed out into space by massive explosions called
supernova. These supernova occur when a star (slide of movie stars)—no, not that kind
of stars (slide of actual stars) that’s better— uses up all of the fuel in its center and
explodes.
In that explosion, some particles are accelerated to extremely high energies and flung out
into space, and if we observe them on earth, they are cosmic rays. Every time this cosmic
ray detector beeps, (or whatever) it is detecting one of those particles, and the majority of
them are tiny pieces of stars which exploded far away in our galaxy.
Because the exploding star is such a hot, energetic environment, it forges atoms together
to make heavier elements.
Cynic: But how is that possible? What do you mean when you say that atoms are
formed? I thought they were elementary. And what does this have to do with FRIB?
Host: It has everything to do with FRIB. FRIB will be a nuclear physics laboratory,
which means the scientists there will be investigating those very questions: How are
different elements formed? How can they change from one element to another? Why are
some elements, like carbon and oxygen, way more common than others like uranium?
In this show we will introduce some of the main ideas of nuclear physics, we will talk
about how experimental facilities like FRIB allow us to learn more about it, and we will
discuss the impact and applications its discoveries will have.
NUCLEAR PHYSICS
4 parts – NucHost, Model, Cynic, Forces
NucHost: Let’s kick off the Nuclear Physics part of our show. I know we just said it,
but who can tell me what nuclear physics is all about? (Atomic Nuclei)
Okay, so we know all of matter we see is made up of atoms, and that atoms look like this
(slide), with a dense, positively charged nucleus in the center, and negative electrons
moving around the outside in a cloud. Nuclear physicists don’t really care about the
electrons—they study the nucleus itself.
If we’re going to talk about nuclear physics, we obviously need a nucleus…so BRING
OUT THE NUCLEUS!
Model: (brings out tennis ball nucleus, NucHost acts like Vanna White?) Here we have a
model of a nucleus. Can anyone tell me what a nucleus is made of?
That’s right—it’s made up of protons, which are positively charged, and neutrons, which
have no electric charge. In our model, we represent the protons as red tennis balls, and
the neutrons as blue tennis balls.
The number of protons, or red tennis balls, determines what kind of element an atom is.
For example, an atom with two protons, (demonstrate) is helium, and an atom with six
protons is carbon, which makes up diamonds and graphite in pencils.
We sort the elements using the Periodic Table (slide), which I’m sure you’ve seen before.
In it, atoms are sorted by atomic number, or number of protons. The atomic mass is the
total number of protons and neutrons combined, since they have approximately the same
mass. For example, our model nucleus which has six protons and six neutrons has a mass
of 12 atomic mass units, and is called carbon-12. (1 amu ~10^-23 g)
NucHost: Later in this show we’ll be talking more about FRIB, which, stands for the
Facility for Rare Isotope Beams. Who can tell me what an isotope is?
(take some responses)
Model: The number of neutrons in a specific element is not fixed. We could add a
neutron to our carbon-12 nucleus to get carbon-13, and we could even add one more to
get carbon-14. Isotopes are atoms of the same element—that is, they have the same
number of protons—but different numbers of neutrons. The atomic masses listed on the
periodic table are the averages of masses for that type of atom as they occur in nature. So
you see, the mass of carbon, as listed on the Periodic table is very close to 12. That’s
because carbon-12 is so much more common than carbon-13, 14, or any other isotope.
This model is obviously much larger than the real thing. An actual atomic nucleus is
about a femtometer across. That’s 10 to the negative 15 meters…(display number on
slide)
NucHost: To give you an idea of how small that is, we have here a binder that contains
pages covered in dots. (show around Million Dot Book) There are one million dots in
this book.
Now picture a meter stick. There are one thousand millimeter markings in a meter. To
get a femtometer, you would first need to divide each of those millimeters into a million
tiny pieces—as many as there are dots in this binder—and then divide each of those
pieces into a million pieces. Can you picture that small of a size?
Model: No.
NucHost: Me neither, but it does mean that our model is about 10^14 times larger than
an actual nucleus—that’s one with fourteen zeros after it.
Model: Okay, so an atomic nucleus is small—that’s expected, right? What amazes me is
how small it is compared to atom it is in. Even though in a lot of diagrams, like the one
on this slide, the nucleus looks like a big ball, comparable to the size of the whole atom,
it is actually much, much smaller—about 10,000 times smaller.
That is to say, if this model, which is about 20cm across were a nucleus in an atom, the
closest orbiting electrons would be about a kilometer away—that’s more than half a mile.
So you see, atoms are mostly empty space.
Cynic: (raises hand frantically) Ooh ooh! I have a question! Pick me!
NucHost: Yes?
Cynic: (walks onto stage, to overhead projector, if available) With electric charges, I
know that opposite charges attract, and like charges repel, like magnets. (demonstrates
with iron filings on overhead projector.) And I know atoms are held together because the
negative electrons are attracted to the positive nucleus.
NucHost: That’s right.
Cynic: So shouldn’t all of the protons in the nucleus repel each other? If they’re all
smushed into such a small nucleus, what keeps the whole thing from just flying apart?
Forces: That’s a great question. The force you’re talking about, which controls the
interactions between charged particles and magnets, is electromagnetism. If it was the
only force affecting the insides of nuclei, they couldn’t exist—the protons would just fly
apart, like you said.
Cynic: So what other force holds them together? Gravity pulls things toward each other,
is that it?
Forces: Gravity is attractive, but compared to electromagnetism, it is much too weak to
hold the positively charged nucleus together. In fact, it’s about 10^36 times weaker!
Something stronger glues all the protons and neutrons in a nucleus together. It’s called
the strong force.
Cynic: Physicists aren’t very creative with names, are they?
Force: Maybe so—but they’re descriptive. To be able to hold two protons together
inside a nucleus, the strong force has to be 100 times stronger than the electromagnetic
force. That means that the bonds that hold atomic nuclei contain a LOT of energy. So
much energy that if you break a nucleus apart, it can be released in a giant explosion, like
from an atomic bomb (picture or video on slide), or in a more controlled way, to produce
nuclear power.
You might wonder why, if the strong force is so, well, strong, we don’t see it’s effects in
our everyday lives, as we do with gravity and electromagnetism. If you drop a ball
(demonstrate) it falls to the ground. If you put two magnets near each other
(demonstrate) they attract or repel. Different voltages produce electric currents, which
power appliances like our projector or the lights in this room.
In fact gravity and electromagnetism are actually just two of four fundamental forces.
We’re familiar with them because they’re long range—that is, we can see their effects in
our everyday lives. The other two forces – which are the strong force, and the (also
descriptively named) weak force -- can only reach very short distances, only about the
size of a nucleus! Because of that, though they have strong effects, they only come into
play when we’re studying things on very small size scales. The strong force, like I was
just talking about, holds the protons and neutrons together in a nucleus. The weak force,
is responsible for radioactive decay, which can turn one kind of particle into another, like
a neutron into a proton.
Model: All of these forces have an effect on the properties of different nuclei. There is a
sort of tug-of-war between them, with the protons wanting to repel each other because
they have the same electric charge, and the nucleons, that is, protons and neutrons,
wanting to stick together because of the strong force. These forces are balanced only in
nuclei with certain numbers of protons and neutrons. We say that these nuclei are stable.
To simulate this, in our model, we have our tennis ball nucleons stuck together with
velcro. The protons have only the soft side of the velcro on them, and the neutrons have
the hook side. So, just like in real nuclei, we can’t just stick two protons together, nor
two neutrons. In fact, in real life, just as with our tennis ball model, nuclei tend to be
more stable if they have approximately the same amount of protons and neutrons.
We can see this if we look at the Table of Nuclei, which is essentially a souped up
version of the periodic table. Instead of having the proton numbers go in little rows, we
have all of them stacked up on the vertical axis. (point out helium, carbon, gold,
whatever, on slide), while the number of neutrons is the horizontal axis. This lets us map
out all the nuclei we know about. You can see the stable nuclei, in (black?) do make a
line where proton and neutron numbers are about equal.
NucHost: Now think about it, if a nucleus is not very stable, will it stay the same for
long? No—if nuclei are unstable, they can break apart into smaller nuclei, spit off
neutrons and protons or, or even turn a neutron into a proton through radioactive decay.
(or the other way around) So would we expect to see more stable or unstable nuclei in
nature?
Unstable nuclei are much less common than stable nuclei, and in some cases appear only
for a short time in special circumstances, such as the stellar explosions of supernovae.
You can see them on the edges of this blob of nuclei, in (color). (gesture at slide.) That
is why they are known as Rare Isotopes.
Because they’re rarer, and exist for short lifetimes, rare isotopes are difficult to study.
Understanding their properties and how they decay, or turn into more stable nuclei, can
tell us a lot about how nuclear physics in general works—and they are what FRIB will be
built to study.
ACCELERATORS AND FRIB
4 parts – Accelerators, Cynic, Businesslike, Collisions(FRIB host)
Collisions – Okay, so we know what rare nuclei are, and a little about what we want to
know about them. But how do we study nuclei? Remember, they're very small, only
about 10^-15 meters across. That's too small for a microscope to look at. (Light
microscopes can only see things down to about half a micron across, a trillion
[1,000,000,000,000] times larger than a nucleus.)
It's a principle of physics that particles with higher energies can probe smaller distances,
and so to look at things as small as nuclei, we use special devices called accelerators.
Right now on MSU’s campus we have an accelerator called the cyclotron which studies
rare isotopes. FRIB is another, bigger accelerator planned for the near future. When it's
built, FRIB will be the largest and most powerful accelerator built solely for studying
nuclei in the world.
Accelerators – You can think of an accelerator as a giant microscope. Think about what
is really going on when you use a normal microscope. You shine light at an object you
want to look at, then look at it with your eye. To use the terminology of nuclear and
particle physics, you have a beam, a target, and a detector. With a light microscope, the
beam is the beam of light you're shining on your sample, your target is the thing you want
to look at, and the detector is your eye, which can record and study how the light beam
bounces off your target.
A nuclear physics accelerator operates on the same principles, but with very different
components. At the MSU Cyclotron laboratory right now, and in the future at FRIB, the
beam is made up of the rare isotopes we were talking about a little while ago. We get a
beam of them going very fast to give them a lot of energy, and then run them into a
target, which is usually a piece of metal foil. Then we use electronic detectors to study
how the beam nuclei and the nuclei in the foil bounce off of each other, which can tell us
a lot about the nuclei involved.
Collisions – But before we're able to do that, we need to get that beam of nuclei going
fast, around 30 to 50% the speed of light, to see interesting collisions. To do this we take
advantage of the fact that after you strip some of the electrons off an atom, it leaves a
positively charged particle – the nucleus, plus maybe a few electrons that happen to stick
around.
You guys have learned about charged particles in your science classes, right? What's a
good way to get a charged particle moving? (take some responses) You use electric
fields.
This sling shot can give a good visual idea of how a particle, or nuclei is accelerated with
an electric field. Let's say that this ping pong ball is a positively charged nucleus, and
that the rubber band on this sling shot is a negative voltage. Positive charges are drawn
towards areas of negative voltage, (like how opposite charges attract) so when we stretch
out the rubber band of this slingshot, it is like the ping pong ball, or nucleus is being
drawn into an area of negative voltage by the electromagnetic force. (demonstrate
slingshot)
Accelerators: To give you an example of a real-life charged particle accelerator, we
have here a cathode ray tube. It works by heating up a filament, on this end, which spits
out a bunch of negatively charged electrons. The electrons are attracted to, and therefore
accelerated towards this positive piece of metal, or cathode. The cathode has a hole in
the middle, so because these electrons are going fast enough, they pass right through it
(like our slingshot). If we turn down the lights, you can actually see this beam of charged
particles. (show)
Collisions: Once we have a beam of charged particles, we want to make sure we can
control where it's going.
We're already using an electric field to accelerate the charged particles. What can we use
to steer where they go? (take responses) When charged particles are moving, we can
bend and steer their paths using a magnetic field. Magnetic fields can be made with
permanent magnets like these (hold up bar magnets). They can also be made using
currents flowing through coils of wire – moving charges make magnetic fields.
These loops around our cathode ray tube are called Helmholtz coils. They are basically
just coils of wire that are spaced apart so they make constant magnetic field in between
them when we turn them on. Watch what happens to our electron beam when we turn on
the magnetic field. (demonstrate)
FRIB will use coils of special, superconducting wires to make very powerful magnetic
fields to steer its very energetic beams of nuclei.
Accelerators: Now, the way the cathode ray tube works is that it accelerates electrons as
they move towards the cathode, but because it stays positively charged, it will exert a
force pulling back on them after they fly through it. This will slow them down a little bit.
We don't want that. You can think of this as the ping pong ball sticking to our slingshot
rubber band, so it gets slowed down a little before it flies away.
What if we shut off the electric field just as the ball, or nucleus was passing through the
slingshot? (shoot ball with sling shot) That way, once the ball passes through our
slingshot, the rubber band just lets go, and the ball flies away just as fast as it was going
when it arrived at the middle of the slingshot accelerator. It wouldn't slow down at all.
With an electric field, if we can switch the sign of the voltage, say on our cathode ray
tube from positive to negative, right when the electrons are going through the little loop,
they would get an extra push away from the cathode, because like charges repel.
In FRIB, this is exactly what will be done. Instead of little loops like in our cathode, the
FRIB accelerator will accelerate bunches of particles through a long line—roughly half a
kilometer long!--of conducting cavities. By alternating the voltage of those cavities at
just the right times, those bunches will be pulled in and pushed out of those cavities in
succession (animation on slide) to get them going faster and faster, until they're going up
to 60% the speed of light.
Cynic: I can actually explain more of this!
Accelerators: Really?
Cynic: Yeah. While you were talking, I was doing some light reading about nuclear
physics accelerators. (holds up a text book or something.)
Accelerators: Go on ahead then.
Cynic: Sweet. Okay, so FRIB will be accelerating particles up to over half the speed of
light. To get particles going that quickly, you need very big voltages. Using a bigger
voltage is like stretching our rubber band slingshot further, which makes the force on the
ping pong ball, or on the nucleus stronger. At FRIB, its cavities will alternate between
positive and negative 1 million volts. That is a huge amount. For comparison, a wall
socket delivers about 120V.
Also, keep in mind that these cavities have to alternate quick enough to be in sync with
the bunch of particles that are moving through them, so that they push and pull at the
right times to accelerate the particle. These particles will be going 60% the speed of
light, which means they could circle the entire earth four times in one second.
Also, when you've got such an energetic beam, the magnetic field required to steer it
must be very strong. To make a stronger magnetic field, you need to put a lot of current
through the coils of wire in your electromagnet.
When current moves through a normal conductor, like we have in our Helmholtz coils,
some of its power is lost through electrical resistance, which heats up the metal. Hotter
metal has larger resistances, which would cause it to heat up more, which would raise the
resistance more, and so on... Basically, there is a limit to how much current you can put
through a metal wire and still have it be useful.
FRIB, and many other modern particle accelerators (like the) get around this problem by
using a special type of materials called superconductors instead of normal metal.
The property that makes superconductors so useful is that if you get them cold enough,
their resistance drops to zero. That means you can put huge amounts of current through
them compared to normal wires.
Here we have a sample of superconducting wire from the cyclotron laboratory. (show
picture on slide as well) Inside is a tiny piece of superconducting wire, surrounded by
metal so that it is easier to bend and shape. Inside the cyclotron and FRIB, wires like
these will be cooled to 4 degrees Kelvin (-269C, -452F) to conduct huge amounts of
current in powerful magnets.
To conduct the same amount of current as this little superconducting wire, a copper wire
would have to be much larger around, like this (show, and have slide pic), to transmit the
same amount of current. Wires this big would mean that the coils for your
electromagnets would have to be very big, which would make setting up experiments
much more difficult and expensive.
We don't have any liquid helium with us, but we can use some liquid Nitrogen, which is
at 77K (-196C, -320F), and this chunk of superconductor to show you one of the neat
properties of superconductors. In addition to having no electrical resistance,
superconductors also have the property of expelling all magnetic field lines. If I put the
superconductor in this dish, and dump in some liquid nitrogen to cool it down, it becomes
superconducting. I also have here a strong magnet. Watch what happens when I put the
magnet over the superconductor. It floats in mid-air! (hopefully we can figure out how
to hook a video camera up to the projector, so everyone can see.)
What's happening is that the superconductor always wants to keep it so there is zero
magnetic field inside of it. As a result, when the field of this magnet approaches the
superconductor, little eddy currents on the surface of the superconductor form, making a
it's own magnetic field which cancels that of the magnet. This causes the magnet to float.
Accelerators: Cool. So FRIB uses superconducing high voltage cavities to speed up a
particle beam, and the uses superconducting coils of wires to make strong magnetic fields
to steer them. Then what happens?
Collisions: Then the beam of fast-moving nuclei gets smashed into a target, which is
usually some kind of metal foil. Say the beam is made up of Carbon-12, with 6 protons
and 6 neutrons, like our model here. (get out tennis ball nucleus again)
The nuclei from the beam will bounce off of the nuclei in the foil. Because the nuclei are
moving so fast and have so much energy, some of them will break apart, or fragment in
collisions, like this. (Drop or throw model nucleus onto floor, or at target of some sort. It
should fragment. Collect the pieces and talk through what the nucleus fragmented into.
Point out on table of nuclei.)
In FRIB, special kinds of detectors will be used to study what kinds of fragments are
made in collisions, and where they go. Just like the way this nuclei fragmented depended
on how all of our tennis balls were stuck together with velcro, the way rare isotopes
fragment will tell us about how the forces in the nuclei hold them together.
Cynic: Hang on-- so studying these fragments are great, but you had some neutrons and
protons and things flying out of that collision. That's nuclear radiation! Isn't that
dangerous!?! (slide of 3-eyed simpsons fish, or somethings similar)
Businesslike: Didn't you read about that too?
Cynic: I didn't get that far yet.
Businesslike: Well, okay. The answer is both yes and no. It's yes because nuclear
radiation can be dangerous, but no because the cyclotron and FRIB have many safety
measures to contain the radiation and to make sure it doesn't cause harm to any workers
at the lab, or to the community around it.
First of all, I should explain that there are really a lot of things in your every day life that
expose you to very small amounts of radiation. Cosmic rays, which we talked about
earlier are one source, we get a little bit from the sky at all times. A lot of types of rocks
and building materials are slightly radioactive as well, but the amount of radiation is
small enough that it hardly affects us. Potassium in bananas and in your blood, and even
the Fluoride in your teeth are slightly radioactive!
Here I have a device called a Geiger counter. It makes a clicking noise when it detects
radiation. When I turn it on, you can listen and hear that even with no radioactive
sources near it, it still clicks every once in a while. That's because there's always a low
level of background radiation. Here I have a few objects that are radioactive-- not to a
dangerous level, don't worry!
(talk through samples, show how Geiger counts increase when you put it closer to
samples)
There are several different types of radiation. Radioactivity is due to high energy
particles coming out of a material or collision, and they type of radioactivity depends on
what type of particle it is made of. Some kinds are very weak, such as alpha radiation,
which is made of helium nuclei. It is coming off of this piece of fiestaware, and can be
stopped with something as thin as a piece of paper. You’d be perfectly safe eating off of
this plate—as long as you didn’t eat the plate itself!
A lot of the radiation from FRIB will be neutrons, which aren't so easily stopped. To deal
with this, the beam and experimental area of FRIB and the cyclotron are surrounded with
giant concrete blocks, and while the experiments are running, no one will be in the room.
All experimenters also wear badges, like this (show picture) while working, which record
how much radioactivity they've been exposed to. Because of all the precautions taken at
the cyclotron, workers there are actually exposed to less radiation there than they would
be outside of the building!
CONCLUSION
Host: Awesome. Thank you guys so much for explaining that! Just to recap, we've
learned that Nuclear physics is the study of atomic nuclei and the forces that hold them
together. Isotopes are nuclei of the same element with different numbers of neutrons, and
some of these isotopes are more stable than others. FRIB will be a powerful accelerator
that will study isotopes that are particularly unstable, or rare. It will do this using
superconductors to speed up the nuclei and steer them into a target, and will use detectors
to study what happens in the collisions.
So why does this matter? Studying nuclear physics can help us better understand the
world around us, and can help us improve technologies like nuclear power production
and the use of radiation in medicine, such as cancer therapy.
In the beginning of our show, we talked about how learning about nuclear physics also
helps us understand astrophysics better-- that is, how elements are made in supernovae.
Now that you know a bit more about nuclear physics, let's revisit that.
Enthusiastic: During most of a star’s lifetime, it keeps its shape by balancing the inward
push of gravity with a pressure created by nuclear fusion explosions inside its core. It
maintains these explosions by burning Hydrogen, that is to say, by combining several
hydrogen atoms together to form helium.
(Get a volunteer to be gravity, or have host do it.) [Balloon demo] You can imagine that
star is initially like this tin-foil wrapped around a balloon. Our volunteer, [name], is
simulating the inward push of gravity by pushing in on this tin foil, by trying to smoosh it
together, and the air inside the balloon, pushing back is like the outward pressure from
those nuclear reactions.
Now, what do you think happens when a star uses up its fuel and the nuclear reactions
inside it stop? It’s like what happens if there is no air in the balloon to provide a
balancing pressure. (pop the balloon with a pin—make sure you don’t prick the
volunteer. They should be able to crunch the tinfoil into a ball. Thank the volunteer,
have them sit down.)
Host: Now when our tin-foil star collapsed, there was energy released when the elastic
energy of the stretched balloon was suddenly relieved. This generates a loud popping
noise. When a star collapses—that is, when the guts of the star that were being held far
away from the center by the pressure from its core suddenly rush inwards. They are
accelerated up to speeds up to 70,000 km/s, and collide into each other, releasing lots of
energy, causing nuclear reactions, and making new kinds of nuclei, or isotopes. Does this
sound familiar?
When we make collisions inside of FRIB, it will be like we are recreating the conditions
inside of supernovae. That fact is pretty awesome on its own, but it gets cooler...
Enthusiastic: The nuclear reactions in a supernova can blow off the whole outside of the
star, leaving a dense core, and can make many heavy elements, like nickel, iron, all the
way up to uranium. If the star is big enough, its core can form a neutron star, which is an
object about 10km across made almost entirely of neutrons, like a giant atomic nucleus—
or even a black hole.
Those heavy elements that are thrown off as part of the outside of the star get dispersed in
the gas and dust inside our galaxy, and over time, as there are more and more supernovae
throughout, the amount of heavy elements build up, and can condense to form more stars,
and planets such as the earth.
Host: That’s right! Everything around you, from this table, to the glass in the window, to
the cells in your body are made from atoms that were made in the explosions of dying
stars—supernovae, the same processes which spit out cosmic rays like we saw in this
cosmic ray detector, and by the processes that will be studied at FRIB.
So when FRIB studies nuclear physics, it will be studying the processes that created the
atoms that make up...well everything. That's part of the reason why nuclear physics
facilities are so fascinating, and so important-- and it's why we thought it was cool
enough to tell you about today.
That's the end of our show. Thank you all for listening. If anyone has any questions, feel
free to ask them now, and when we're done, feel free to come up and chat with us if you'd
like to get a closer look at any the equipment we used in our show.