1 Antimatter 1Antimatter and the Universe 2Antimatter in the Laboratory 3Antimatter in Daily Life.

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Antimatter

1 Antimatter and the Universe

2 Antimatter in the Laboratory

3 Antimatter in Daily Life

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CERN Aerial View

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1 Antimatter and the Universe

Big Bang

13.7 billion years ago

How did the energy transform into mass ?(…and atoms, stars, planets)

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Antimatter

Werner Heisenberg (Nobel prize 1932, on quantum theory)

”I think that this discovery of antimatter was perhaps the biggest jump of all the big jumps in physics in the 20th century.”

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Dirac : Key DiscoveryNobel prize 1933

Paul A. M. Dirac

Relativity + Quantum Theory

‘‘Antiparticles’Antiparticles’

Energy*

* gamma raysantiparticle

particle

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Properties of Antimatter

Every particle has an antiparticleExample: Electron: Mass = 0.511 (MeV) Charge = -1

Positron: Mass = 0.511 (MeV) Charge = +1

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Is the Universe symmetric?1933 Dirac (from his Nobel lecture)

“If we accept the view of complete symmetry between positive and negative electric charge so far as concerns the fundamental laws of Nature, we must regard it rather as an accident that the Earth (and presumably the whole solar system), contains a preponderance of contains a preponderance of negative electrons and positive protons.negative electrons and positive protons.

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It is quite possible that for some of the stars it is the other way about, these stars being built up mainly of positrons and these stars being built up mainly of positrons and negative protons. In fact, there may be half the stars of negative protons. In fact, there may be half the stars of each kind. each kind.

The two kind of stars would both show exactly the same spectra, and there would be no way of distinguishing themno way of distinguishing them by present astronomical methods.”

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We are still searching the answers.

Search for cosmic antimatter

Road No. 1:

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The Search for Antimatter

Anti-Nuclei?

Gamma-rays ?

Solar system?

AMS

NO …

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Clue:

Our Universe is filled with light !

The Antimatter Mystery

Big Bang: 50 % Antimatter

Now: 0 % Antimatter

How did Antimatter disappear?

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Without asymmetry - we would not be here!!

What kind of asymmetry??

Possible Story Line - The “Annihilation Battle”

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Sakharov’s Idea

A.D.Sakharov

Particles decay (a little) faster than antiparticles*

Small imbalance (1,000,000,001:1,000,000,000)Occurs during cool-down of Universe

Most particle-antiparticle pairs annihilate to radiation

Galaxies, stars, planets, us = ‘left-over’

*For experts: this is called ‘CP violation’

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Could matter and antimatter be different?

Fundamental theorem* of physics : “NO” !!

*For experts: the ‘CPT theorem’

Experimental physics : “let’s see … “

Compare properties of

particles with antiparticles

Mass - charge - magnetic momentmagnetic moment - lifetime ?

For example: Compare electrons and positrons

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Precision measurements

rugth30.phys.rug.nl

Electron and Positron are like small magnets.

Their magnetic fields are identical to better than

Many similar tests - no asymmetry found!

But: symmetry violating effects will be very small (if any)

0.000 000 000 1 %0.000 000 000 1 %

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ANTIHYDROGEN - a new precision tool

Best known and simplest (anti) atom

High precision lasers probe energy levels

Comparison: 1 part in 1018 ?

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Anti-Gravity ??

Repeat Galileo’s experiment with (neutral) antihydrogen

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2 Antimatter in the Laboratory

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How to study the Big Bang?

Collision and detection of accelerated particles

Kinetic energy is transformed into new particles

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History of the CERN pbar source•1980-1986 AA

•3.57 GeV/c Antiproton Accumulator ring;

1012

pbars stored (peak). p/pbar collisions in SPS

+ low energy experiments in LEAR

•1986-1996 AAC (AA+AC)•Large acceptance Antiproton Collector ring added.

Production rate increased 10-fold to 6*1010

pbars/h

•1998 - ? AD•AC converted from fixed energy storage ring to

Decelerator. 5*107 pbars slowed down to 100 MeV/c

(5.3MeV kinetic). Local experimental area.

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Antiproton Production today

50,000,000 antiprotons (per 90 s)

Needs (at least) 6.2 GeV of (proton) energy

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Cool Antiprotons …

Antiprotons produced at speed of light

Slow antiprotons down to (almost) rest

Accumulate positrons

Mixing for antihydrogen formation

… Cold Antihydrogen

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Antiproton Decelerator (AD)

Make antiprotons

Slow to 10 % of c

Eject to experiments

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Pbar production

Ir target, cooled 400kA Magnetic Hornfor focussing

•1.5*1013 protons yield 5*107 pbars

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Pbar production

Magnetic fieldsused to filterparticlesw. correctpolarity/energy

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AD cycle

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Stochastic cooling

ALPHA

Slot-line type pickup and kicker

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Electron cooling

30kV 2A electron beam mixed w. pbarsthermal exchange, continuously renewed beam

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View of AD experimental area

ALPHA and ATRAP: study antihydrogen

ASACUSA: study antiprotonic Helium spectrum

ACE: cell irradiation

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Antiproton trapping

QuickTime™ and aAnimation decompressor

are needed to see this picture.

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3 Antimatter in Daily Life

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Antiparticles store energy

Mass is condensed energy

(c2 = exchange rate!)

1 kg = 9 · 101 kg = 9 · 101616 J = 2.5 · 10 J = 2.5 · 101010 kWh = 2.85 GW·year kWh = 2.85 GW·year

(drive VW Polo for 100,000 years without stop)(drive VW Polo for 100,000 years without stop)

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Production ~ 1,000,000,000,000,000 antiprotons/year

Antimatter in large quantities?

Only 0.000 001 milligramme (3 sec on VW Polo) !!

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Antiproton Tumour Therapy?

Antiproton range 0.1 - 15 cm

Annihilation

Local destruction(nuclear fragments)

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First results are encouraging

Antiproton Cell Experiment

(at CERN)

Explores antiproton annihilation in cells

Comparison with protons, heavy ions

Nuclear fragments have short range:

Destroy surrounding tissue (<< 1 mm)

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Summary

Antimatter research helps us understand the origin of our (matter) Universe

Antihydrogen is an important new tool for precision studies (also gravitation!)

Medical applications of antimatter are of great interest