1. Cold Antimatter at CERN
The ATHENA, ALPHA and AEGIS Experiments at the AD
Lars V. Jørgensen – CERN

2. Lars V. Jørgensen – CERN - June 19, 2012
Outline
What is antimatter?
Why is it interesting?
Pure research
Practical uses?
How do we make it?
Making atoms of it
Holding on to the atoms
Lars V. Jørgensen – CERN - June 19, 2012

3. Lars V. Jørgensen – CERN - June 19, 2012
Antimatter – What is it?
An equation from Quantum Mechanics 2
X = K
Dirac’s equation:
(1928)
Has 2 solutions
One positive
One negative
Positive solution fits normal matter
i.e. electron, protons, etc.
What is the negative solution ???
Lars V. Jørgensen – CERN - June 19, 2012

4. Lars V. Jørgensen – CERN - June 19, 2012
Antimatter – What is it?
Anti-particles:
Opposite charge
Same mass
Exactly cancels out it’s normal matter ‘partner’
Lars V. Jørgensen – CERN - June 19, 2012

5. The first antimatter is discovered.
Carl Anderson at Cal Tech
observes the first positron
from cosmic ray showers
in 1932
Quick Nobel Prizes:
Dirac 1933
Anderson 1936
Lars V. Jørgensen – CERN - June 19, 2012

6. Discovering more anti-particles
E = m c 2
Mass is energy (nuclear power)
But also: Energy is mass
High Energy Physics !!
Pair Creation:
With high enough energy
a pair of matter-antimatter
Particles can be created
Antiproton – 1955
Antineutron – 1957
Antideuteron – 1965
Antihelium-3 – 2011!
Surrounding Edward Lofgren (center), head of the
Bevatron, are discoverers of the antiproton, (left to right)
E.Segre, C.Wiegand, O. Chamberlain and T.Ypsilantis.
Lars V. Jørgensen – CERN - June 19, 2012

7. Lars V. Jørgensen – CERN - June 19, 2012
Anti – atoms?
In atoms of antihydrogen was made at CERN’s LEAR machine
All these atoms were at very high energy
To study antihydrogen we need it at much lower energies
CERN’s LEAR Machine
CERN built the
AD (Antiproton Decelerator)
to achieve this!
It started operation in 2000
Lars V. Jørgensen – CERN - June 19, 2012

8. Why is antimatter interesting?
Why are we here?
If the Big Bang was Pair Creation there should be equal amounts of matter and antimatter in the universe
We know from measurements that there is almost no antimatter in the universe
Why is this ??
Antimatter at the
center of the Milky Way
Lars V. Jørgensen – CERN - June 19, 2012

9. Fundamental studies of anti-hydrogen
CPT tests
Fundamental studies of anti-hydrogen
“Hänsch Plot”
Spectroscopy – checking if the energy-levels are the same in hydrogen and antihydrogen
This tests some very fundamental theories in physics – the standard model and the CPT Theorem (C=charge, P=parity and T=time)
Lars V. Jørgensen – CERN - June 19, 2012

10. Lars V. Jørgensen – CERN - June 19, 2012
What about Gravity?
Does antimatter fall up ??
Gravity is a very, very weak force
compared to the other forces
e.g. Electro-magnetism
This makes an experiment VERY
difficult
- but neutral atoms are necesary
Theory is not so clear !
... But most people expect it to behave like matter
New experiment at the AD now under construction:
AEGIS - Antimatter Experiment: Gravity, Interferometry, Spectroscopy
Lars V. Jørgensen – CERN - June 19, 2012

11. Are there practical things where antimatter might be useful ?
PET scanners (Positron Emission Tomography)
Treating cancer with antiprotons (The ACE experiment)
Lars V. Jørgensen – CERN - June 19, 2012

12. Passing into the antiworld?
France
Switzerland AD PS
LINAC2
Lars V. Jørgensen – CERN - June 19, 2012

13. How do we make anti-matter ?
Lars V. Jørgensen – CERN - June 19, 2012

14. Lars V. Jørgensen – CERN - June 19, 2012
Making antihydrogen e p _ +
Na22 source
We take antiprotons and slow them down MUCH, MUCH more
We collect a lot of positrons
We get them together
They make antihydrogen and fly to the wall
We detect them
Lars V. Jørgensen – CERN - June 19, 2012

15. Detecting that we have made antihydrogen
We build a detector that can measure the annihilation of an antiproton and a positron at the same time and at the same place
Lars V. Jørgensen – CERN - June 19, 2012

16. Next step: Trapping antihydrogen
Antihydrogen Trapped!
Nature, 17 Nov. 2010
More antihydrogen
trapped
for 1000 seconds!
Nature Physics, 5 June 2011
quadrupole winding
mirror coils
Ioffe-Pritchard Geometry
How
???
Antihydrogen or hydrogen are tiny magnets – kinda!
We use this to try to trap them
Difficult as charged antiprotons and positrons must also survive
Very weak trapping field: 1 T ~ max. 0.7 K
Lars V. Jørgensen – CERN - June 19, 2012

17. Ready for spectroscopy?
Antihydrogen trapped
Antihydrogen in ground state
Survives for a long time
Not very many anti-atoms at any given time (max 1 so far)
No laser access yet
Microwaves !!
First investigation of the internal state of ground state antihydrogen – Nature, March 2012
Lars V. Jørgensen – CERN - June 19, 2012

18. The AEGIS experiment Measuring g for antihydrogen to about 1%
Under construction
Should take first
beam at end of 2011
Results? ?
Does antimatter fall up ??
Lars V. Jørgensen – CERN - June 19, 2012

19. Lars V. Jørgensen – CERN - June 19, 2012
See the real thing!!!
Let’s go down to the AD and have a look!!!
Lars V. Jørgensen – CERN - June 19, 2012

20. The ATHENA Collaboration
35 physicists
Lars V. Jørgensen – CERN - June 19, 2012

21. The ALPHA Collaboration
Lars V. Jørgensen – CERN - June 19, 2012

22. Lars V. Jørgensen – CERN - June 19, 2012
LAPP, Annecy, France G. Drobychev, D. Sillou
Queen’s U Belfast, UK G. Gribakin, H.R.J.Walters
INFN Firenze, Italy G.Ferrari, M. Prevedelli, G. Tino
CERN M. Doser, A. Duradev, T. Eisel, F. Haug, T. Niinikoski, D. Perini , J. Bremer
INFN Genova, Italy C. Carraro, V. Lagomarsino, G. Manuzio, G. Testera, R. Vaccarone, S. Zavatarelli
MPI-K Heidelberg C. Canali, R. Heyne, A. Fischer, A. Kellerbauer, C. Morhard, U. Warring
Kirchoff Inst. Of Phys., Heidelberg, Germany M. Oberthaler
INFN Milano, Italy I. Boscolo, N. Brambilla, F. Castelli, S. Cialdi, L. Formaro, A. Gervasini, M. Giammarchi, F. Leveraro, A. Vairo
INR Moscow, Russia
A.S. Belov, S. Gninenko, V. A. Matveev, A. V. Turbabin
ITEP Moscow, Russia
W. M. Byakov, S. V. Stepanov , D.S. Zvezhinskij
Université Claude Bernard, Lyon, France
P.Nedelec
New York Univ. USA
H.H. Stroke
University of Oslo and University of Bergen, Norway
O. Rohne, S. Stapnes, H. Sandacker
INFN Pavia-Brescia, Italy
G.Bonomi, A. Fontana, C. Riccardi, A. Rotondi, A. Zenoni
Czech Tech. Univ, Prague, Czech Republic
V. Petracek, D. Krasnicky
IRNE Sofia, Bulgary N. Djurelov
INFN Padova-Trento, Italy
R.S. Brusa, D. Fabris, M. Lunardon, S. Mariazzi, S. Moretto, G. Nebbia, S. Pesente, G. Viesti
ETH Zurich, Switzerland
S.D. Hogan, F. Merkt
Qatar University
I. Y. Al-Qaradawi, L. V. Jørgensen
PolitecnicoMilano, Italy
G. Consolati, A. Dupasquier, R. Ferragut, P. Folegati, F. Quasso
La. Aime’Cotton, Orsay, France
L. Cabaret, D. Comparat
Lars V. Jørgensen – CERN - June 19, 2012