Cold Antimatter at CERN

Cold Antimatter at CERN

The ATHENA, ALPHA and AEGIS Experiments at the AD

Lars V. JLars V. Jøørgensen – Swansea Univ. / CERNrgensen – Swansea Univ. / CERN

Lars V. Jørgensen – CERN - June 23, 2011Lars V. Jørgensen – CERN - June 23, 2011

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


Antimatter – What is it?

An equation from Quantum MechanicsAn equation from Quantum Mechanics

X = KX = K22

Has 2 solutionsHas 2 solutions•One positiveOne positive•One negativeOne negative

Positive solution fits normal matterPositive solution fits normal matteri.e. electron, protons, etc.i.e. electron, protons, etc.

What is the negative solution ???What is the negative solution ???

Dirac’s equation:Dirac’s equation:(1928)(1928)


Antimatter – What is it?

Anti-particles:• Opposite charge• Same mass• Exactly cancels out it’s normal

matter ‘partner’


The first antimatter is discovered.

Carl Anderson at Cal TechCarl Anderson at Cal Techobserves the first positron observes the first positron from cosmic ray showersfrom cosmic ray showers in 1932in 1932 Quick Nobel Prizes:Quick Nobel Prizes:

Dirac 1933Dirac 1933Anderson 1936Anderson 1936


Discovering more anti-particles

E = m c

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.

22

Mass is energy (nuclear power)Mass is energy (nuclear power)-But also: Energy is massBut also: Energy is mass

High Energy Physics !!High Energy Physics !!

Pair Creation:Pair Creation:With high enough energyWith high enough energya pair of matter-antimattera pair of matter-antimatterParticles can be createdParticles can be created

Antiproton – 1955Antiproton – 1955Antineutron – 1957Antineutron – 1957Antideuteron – 1965Antideuteron – 1965Antihelium-3 – 2011!Antihelium-3 – 2011!


Anti – atoms?• In 1995 9 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 MachineCERN’s LEAR Machine

CERN built the CERN built the AD (Antiproton Decelerator)AD (Antiproton Decelerator)to achieve this!to achieve this!It started operation in 2000It started operation in 2000


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 Antimatter at the center of the Milky Waycenter of the Milky Way


CPT tests

• 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)

Fundamental studies of anti-hydrogen “Hänsch Plot”


Does antimatter fall down ??

Gravity is a very, very weak forcecompared to the other forcese.g. Electro-magnetism

What about Gravity?

This makes an experiment VERY This makes an experiment VERY difficultdifficult - but neutral atoms are necesary- but neutral atoms are necesary

New experiment at the AD now under construction:New experiment at the AD now under construction:AEGIS - Antimatter Experiment: Gravity, Interferometry, SpectroscopyAEGIS - Antimatter Experiment: Gravity, Interferometry, Spectroscopy

Theory is not so clear ! Theory is not so clear ! ... But most people expect it to behave like matter... But most people expect it to behave like matter


Are there practical things where antimatter might be useful ?• PET scanners (Positron Emission

Tomography)• Treating cancer with antiprotons

(The ACE experiment)

Passing into the antiworld?


ADAD

PSPS

LINAC2LINAC2

FranceFranceSwitzerlandSwitzerland


How do we make anti-matter ?


Making antihydrogen

• 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

ep_

+

Na22 source


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

Silicon microstrips

CsIcrystals

511 keV

511 keV


Next step: Trapping antihydrogen

• 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

quadrupole winding mirror coils

Ioffe-Pritchard Geometry

How How ??????

Antihydrogen Trapped!Antihydrogen Trapped!NatureNature, , 17 Nov. 201017 Nov. 2010

More antihydrogen More antihydrogen trapped trapped

for 1000 seconds!for 1000 seconds!Nature PhysicsNature Physics, , 5 June 20115 June 2011

How ALPHA did it!


Ready for spectroscopy?

Antihydrogen trappedAntihydrogen in ground stateSurvives for a long timeNot very many anti-atoms at any

given time (max 1 so far)No laser access yetMicrowaves !!


The AEGIS experiment


Measuring Measuring gg for antihydrogenfor antihydrogento about 1%to about 1%

Does Does antimatter fall antimatter fall

up ??up ??

- Under constructionUnder construction- Should take first Should take first beam at end of 2011beam at end of 2011- Results? 2014-2015?Results? 2014-2015?


See the real thing!!!

Let’s go down to the AD and have a look!!!Let’s go down to the AD and have a look!!!


35 physicists

The ATHENA CollaborationThe ATHENA Collaboration


The ALPHA CollaborationThe ALPHA Collaboration


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

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Cold Antimatter at CERN