Transcript Dr Robert Flack UCL Institute of Origins 21 May 2009 Institute of origins.

Dr Robert Flack
UCL Institute of Origins
21 May 2009
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The plot
• Antimatter is stolen from
CERN’s Large Hadron
Collider and hidden in
Vatican City.
• Countdown to Vatican
annihilation begins.
• Race through Rome to
avert death and destruction.
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The Lecture
• Antimatter:
– What is it?
– Where does it come from?
– Is an antimatter bomb really viable?
– Can we use it peacefully?
– How does it fit into particle physics?
• Particle physics in the UK and UCL in particular.
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Physics Angels
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Demons
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Matter - the Atom
Rutherford 1908
The conventional view
of the atom:
Electrons in orbit
around the nucleus
Protons and neutrons
~ 2000 times bigger
than the electron
Effectively all of the
mass is in the nucleus
There are other particles but we
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Electron - negative
electric charge
JJ Thompson 1897
Nucleus:
Protons - positive
electric charge
Neutrons - zero
electric charge
Chadwick 1932
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Electron
Proton
How is matter built?
Neutron
Hydrogen
Helium
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Oxygen - 8 protons,
8 electrons.
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What is antimatter?
Proposed by Paul Dirac 1927-30
Every particle has an antimatter counterpart
Their masses are equal
They have equal but opposite electric charge
Electron: negative charge - Positron: positive charge
Proton: positive charge - Antiproton: negative charge
Neutron: zero charge - Antineutron: zero charge
Does the neutron break the rule?
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When matter meets antimatter?
Radiation
+
Particles
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Exploited in matter/antimatter
colliders
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Quarks
The neutron is not a fundamental particle, nor is the proton.
They are composite objects made up of quarks called up and down.
Charge +2/3
Charge -1/3
down
up
up
up
down
up
down
Proton
down
Neutron
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The electron is not
a composite
particle
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electron
Building a Universe
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Building a Universe
electron
proton
neutron
Multiply by billions and billions and billions and billions…
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NASA, ESA/JPL-Caltech/B. Mobasher (STScI/ESA)
© NASA
BUILDING A UNIVERSE
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Nature makes antimatter - Cosmic rays
Cosmic rays are mostly
very high energy protons
entering the atmosphere.
The result of these high speed
collisions with the atmosphere
makes a shower of particles and
antiparticles.
But we still don’t know the true origin of the protons.
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They have such high energies
don’t know how nature does14it
Cosmic rays are more than just positrons!
Proton
Many more particles discovered:
Pions - π (quarks)
Muons - µ (big electrons)
Neutrinos - ν (smallest particle)
And more!
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First observation of antimatter
Discovered by Carl Anderson - 1932
by looking at cosmic rays
Magnetic field directed
into the slide
Electron would curve this way
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Positron
Moving downwards
Lead barrier:
Slows the
particle
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Nature makes antimatter - Radioactivity
Becquerel, Curie, Meitner
Some substances are unstable and emit particles such
as electrons, positrons, radiation along with neutrinos.
Potassium-40
The ones you will have heard of are Uranium,
Plutonium and Polonium. There are many more.
Potassium is used in the body and it contains a small
amount of radioactive potassium, potassium-40.
It emits 400 positrons per second.
positron
neutrino
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We are all radioactive
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producers of antiparticles
How do we make an antimatter bomb?
What is a bomb?
Explosive
Containment
Ignition system
Delivery system
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Energy - James Joule (Manchester 1843)
The proper unit of energy is the Joule (J)
A Trivial example:
Drop a 2.5kg house brick from the top of a house (4m).
It will have 100J of energy when it hits the ground.
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How much energy does a “conventional” bomb have?
1kg of TNT releases 4,184,000 J of energy
TNT – Trinitrotoluene
C6H2(NO2)3CH3
Or 41,840 house bricks!
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Compare with a nuclear bomb
One of the original
bombs that was used
on Japan at the end
of WWII.
Vulcan Bomber
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Destructive power
20Mton of TNT releases 8,368,000,000,000,000 J of energy
8,3630,000,000,000
house bricks!
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How much energy do particles have?
This is the only equation we need but you have seen it before.
E = mc2
Einstein 1906
Electron is very small
0.000000000008 J
(11 zeros)
Proton is much larger
0.0000000016 J
(8 zeros)
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Particles have veryInstitute
small
amounts of energy
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Production of antiprotons
Tevatron - Fermilab, Chicago
Fermilab
Antiproton Decelerator - CERN
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Production of antiprotons
Both work on a similar principle.
Protons are fired at a beryllium target.
The protons decelerate very quickly and lose energy.
The lost energy creates antiprotons (and other particles).
The antiprotons are captured.
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How much antimatter?
1Mton of TNT releases 418,400,000,000,000 J of energy
For 1 Megaton need 3x(25 zeros) anti-protons
= 100g anti-hydrogen
In one year we only produce 1 pico gram
(0.0000000000001g)
Estimated cost $1000trillion = national debt
Need 1,000,000,000,000 yrs to produce enough
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Longer than the
age
of the Universe!
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Containment of antimatter
© CERN
Portable?
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Is an antimatter bomb viable?
Too long to produce enough antimatter
Not portable
Too expensive
No!
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Can we use antimatter constructively?
Medicine - a tool in the Doctor’s armoury.
Fundamental research.
Futuristic uses.
Yes!
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PET Scanners
Courtesy NIH
Positron Emission Tomography
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Non-destructive testing - metal fatigue
•Defects begin from the inside and cannot be seen.
•Positrons can penetrate and annihilate with the electrons
and produce radiation.
•The spectrum of the radiation can pin-point problems.
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CERN - Near Geneva in Switzerland
Thousands of members of
the public take tours of
the laboratory
Before the LHC was switched
on the public could go down
and see the machine during
construction.
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CERN
• European Laboratory for
Particle Physics
• Founded in 1954
• 20 member countries
• More than 9,000 scientists
• Over 100 nationalities
• More than 1,000 from UK
universities and laboratories
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CERN
•Its main function is to carry out fundamental research for
the benefit of all.
•Not to make money.
•Classic example is the world wide web.
-Invented by Tim Berners-Lee 1980-90 whilst working
at CERN.
-CERN has never made any money from it.
-Tim has not received royalties.
George Charpak (frisby man in the book)
Nobel prize 1992
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Hollywood CERN
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THE REAL LHC
• The world’s most powerful particle accelerator
• 27km around, 100m underground
• 4 detectors - ATLAS, LHCb, ALICE and CMS
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Fours detectors
Overall view of the LHC experiments
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THE REAL LHC
Will smash protons into each
other…
…to solve some of the
universe’s biggest mysteries
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The energy is so high
it isofaorigins
quark/quark collider
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UCL - ATLAS
Dr. Nikos
Konstanstinidis
Prof. Jon
Butterworth
Dr. Mario
Campanelli
Dr. Simon
Dean
Dr. James
Monk
Dr. Emily
Nurse
Dr. Erkcan
Ozcar
Dr. Peter
Sherwood
Dr.ofBen
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Waugh
Dr. Sebastian
Boeser
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UCL - ATLAS
And there’s more!
Lily Asquith
Tom Byatt
Gordon Crone
Derek Atree
Janet Fraser
Tony Hoare
Michael Nash
Martin Postranecky
Alex Richards
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Sarah Baker
Brian Anderson
James Robinson
Chris Taylor
Brinick Simmons
Adam Davison
Matthew Warren
Catrin Bernius
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Higgs Boson
Credited to former UCL
Lecturer Peter Higgs 1964.
How we acquire mass.
Still not observed.
LHC will search for it.
The nick-name “God particle”
is from the title of Leon
Lederman’s book.
We don’t use the name and it
has no religious significance.
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Cartoon description byInstitute
Emeritus
Prof. David Miller, UCL.
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Big Bang
Friedman, Lemaitre ~1922-27
Edwin Hubble observed that the
galaxies are moving away from each
other.
Therefore they were closer together in
the past.
13 billion years ago the universe began
with the creation of equal amounts of
particles and antiparticles.
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We don’t yet know precisely why
matter
now dominates over antimatter
Neutrinos
Pauli 1930
First observed by Cowan and Reines 1956
We know they are produced by radio-active elements.
We know they are produced in the sun.
Intriguingly there should be very, very high energy ones.
Neutrinos could be the exception to the “anti-particle rules”
They are not a composite particle like the neutron
It could be its own antiparticle, but is it?
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Photographs of the Sun
Visible light
Neutrinos
This is the inside!
This is the outside
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SuperNEMO
This is the proposed
experiment to measure
the mass of the
neutrino.
It will also tell us if it
is its own antiparticle
It will be housed in the
LSM in France
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Start building
in 2010
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Dr. Ruben
Saakyan
Prof. Jenny
Thomas
Anna
Holin
SuperNEMO group
Dr. Dave
Waters
Anastasia
Freshville
Dr. Rob
Flack
Ben
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Richardson
Matt
Kauer
Dr. Justin
Evans
Dr. Gianfranco
Sciacci
Dr. Zornitza
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Daraktchieva
ANITA
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Looking for very, veryInstitute
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Meeting in antartica
Matthew Mottram
Dr. Amy
Connolly
Dr. Ryan Nichol
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Dr. Simon
Bevan
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The future for antimatter?
Proton - antiproton annihilation
produces 10 billion times more energy
than for example an equal amount of
oxygen/ hydrogen propulsion
1g = 23 shuttle tanks.
The antiprotons are then stored
on the space-craft in an electromagnetic trap.
As with all of these ideas the problems remain the same:
(i) Production of sufficient antimatter
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(ii) Long term storage.
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Conclusion
• We cannot construct an antimatter bomb.
• Antimatter is not “new”, we have known about
it since 1927.
• Producing antimatter has no religious meaning.
• The UK has been and still is a world leader in
particle physics.
• UCL has a large, vibrant and world class
particle physics group.
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Thankyou
•
•
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•
•
•
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•
Clare Jenner - Institute of Origins
Christine Johnstone - Dept. Secretary
Simon Bevan - Post Doc
Alex Richards - Post Grad
Matt Kauer - Post Grad
Shiva King - Post Doc -Teacher - Musician
James Monk - Post Doc
Mark Lancaster - Head of group - supplier of beer
curry and anything else I can blackmail him for.
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Physics Angels
Dirac
Joule
Rutherford
Berners-Lee
Thompson
Pauli
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Chadwick
Curie
Einstein
Meitner
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Backup slides
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Physics Angels
Dirac
Meitner
Rutherford
Thompson
Einstein
Feynman
Chadwick
Fermi
Curie
Oppenheimer
Anderson
Segre
Planck
Joule
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Pauli
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First cosmic rays
Victor Hess is credited with the
discovery of cosmic rays during
1911-1912
He ascended in balloons 10
times and found that the amount
of radiation increased with
height.
He inferred from this that the
radiation came from space and
not from the Earth.
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Pierre Auger Observatory (hybrid design)
The observatory is based in Argentina
Observing particles with very high energy.
Which direction did they come from?
What is their composition?
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Energy much greater than weInstitute
can produce
10th May 2007
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Big Bang: “Where did it come from? You may well ask. I
don’t know and nor, in my opinion, does any other
scientist with certainty. Questions Concerning existence
‘before’ this singular happening are wracked with
philosophical debate as to whether they are even
meaningful: what means ‘before’ if there was no space
or time?
Some popular descriptions seem content to portray a
will-o’-the-wisp universe which erupted as a quantum
fluctuation out of nothing. Maybe it did, but if so then I
would feel compelled to ask why it bothered.
Questions relating to the ‘spontaneous’ appearance
of that first flash of searing heat that we loosely call
the Big Bang begin with ‘why’ and, as such, are
beyond (current) experimental scientific enquiry.
Frank Close: Lucifer’s Legacy.
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Basics on matter-2
Unit of energy in physics:
The proper unit in physics is the Joule (J) - named after James Joule ~1843
Example: 1kg bag of sugar drops 1 meter has 10 J of energy when it hits the floor
Particles have very small amounts of energy:
Example: An electron moving in a 1 volt electric field has only
0.00000000000000000016 J of kinetic energy (19 decimal places) = 1.6 x 10-19 J
We call this 1 electron volt - 1eV
£16000000000000000000.0 = £1.6 x 1019 (National debt)
Light acts like a particle - photon
Visible light is a low energy photon - 1eV
X-rays are high energy photons - keV
Gamma rays are even higher energy photons - MeV, GeV, TeV
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What is a bomb?
• It is a release of a large amount of energy (exothermic
reaction) in a very short period of time.
– 1g of TNT releases 4184 J of energy
– 1tonne of TNT releases 4184000000 J of energy (4.184 x 109)
• For example if this amount of energy was released over
the period of a year then it is not a bomb but a power
station
• Also called irreversible reactions – if we run the clock
backwards we cannot put all of the bits back together
(increase in entropy).
Entropy will get you in the end
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ANITA -
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Hydrogen:
1proton + 1electron
Helium:
2protons + 2 neutrons + 2electrons
Radioactive
Uranium (2 types):
92 protons + 146 neutrons
92 protons + 143 neutrons
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Standard Model
• Table of particles and force carriers.
• Gravity does not fit.
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