AE IS - Jyväskylän yliopisto · Particle, manipulation techniques in AE IS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy)C. Canali INFN sez. Genova (AEgIS coll.)

Particle, manipulation techniques in

AE IS

(Antimatter Experiment: Gravity, Interferometry, Spectroscopy)

C. Canali

INFN sez. Genova

(AEgIS coll.)

TCP2010 April 12-16, 2010 Saariselkä

TCP2010 April 12-16, 2010 Saariselkä C. Canali

LAPP, Annecy,

France

D. Sillou

Queen’s U Belfast,

UK

G. Gribakin,

H. R. J. Walters

U of Qatar, Doha,

Qatar

I. Al-Qaradawi

L. V. Jorgensen

INFN Firenze, Italy

G. Ferrari,

M. Prevedelli

CERN, Geneva,

Switzerland

J. Bremer, G. Burghart,

M. Doser, A. Dudarev,

T. Eisel, F. Haug,

D. Perini

INFN Genova, Italy

C. Canali, C. Carraro,

L. Di Noto, D. Krasnický,

V. Lagomarsino,

G. Manuzio, G. Testera,

R. Vaccarone,

S. Zavatarelli

MPI-K, Heidelberg,

Germany

A. Kellerbauer,

U. Warring

U of Heidelberg,

Germany

P. Bräunig, F. Haupert,

M. K. Oberthaler

U of Lyon, France

P. Nédélec

INFN Milano, Italy

I. Boscolo, F. Castelli,

S. Cialdi,

M. Giammarchi,

M. Sacerdoti,

D. Trezzi, F. Villa

Politecnico di

Milano, Italy

G. Consolati,

R. Ferragut,

A. Dupasquier

INR, Moscow,

Russia

A. S. Belov,

S. N. Gninenko,

V. A. Matveev

New York U, USA

H. H. Stroke

Laboratoire Aimé

Cotton, Orsay,

France

L. Cabaret,

D. Comparat

U of Oslo, Norway

J. P. Hansen,

O. Rohne, H. Sadake

INFN

Padova, Trento,

Italy

G. Nebbia, R. S. Brusa, S.

Mariazzi

INFN

Pavia/Brescia, Italy

G. Bonomi, L. Dassa,

A. Fontana,

C. Riccardi, A. Rotondi,

A. Zenoni

Czech Technical U,

Prague, Czech

Republic

V. Petráček

INRNE, Sofia,

Bulgaria

N. Djourelov

ETH Zurich,

Switzerland

S. D. Hogan, F. Merkt

• Physical motivations: why antimatter?

• Gravity and antimatter

• AEGIS: measuring g on antihydrogen

• Apparatus overview

• Measuring g on H

• Inside AEgIS: particle manipulation techniques

• Diocotron jump of plasma at low magnetic field

• Cooling down antiprotons

• Conclusion

AEGISAntimatter Experiment: Gravity, Interferometry, Spectroscopy

• Physical Motivations: why antimatter?








• Conclusion


Antimatter system:

• WEP test

• General Relativity test

Gravity:

• Spectroscopy on antihydrogen

CPT:

10-1810-1510-1210-910-6

relative precision

Magnetic moment (g - 2)e- e+

(g - 2)μ- μ+

(q/m)e- e+

Mass differencefK0 K0

Charge/mass (q/m)p p

[P. B. Schwinberg et al., Phys. Lett. A 81 (1981) 119]

[R. S. Van Dyck, Jr. et al., Phys. Rev. Lett. 59 (1987) 26]

[G. Gabrielse et al., Phys. Rev. Lett. 82 (1999) 3198]

[Y. B. Hsiung, Nucl. Phys. B (PS) 86 (2000) 312]

[G. W. Bennett et al., Phys. Rev. Lett. 92 (2004) 161802]

We need neutral (cold) antimatter:

Anti-hydrogen!

High precision spectroscopy:

The frequency of the 1S-2S transition in

hydrogen has been measured with high

precision:

f = 2 466 061 413 187 103(46) Hz

[M. Niering et al.,

Phys. Rev. Lett. 84 (2000)

5496]

Spectroscopy on antihydrogen could

be a very precise test of CPT

Charged particles are extremely sensitive

to electric fields: we need a neutral system…

Gravity measurement (AEgIS):

mVE /1067

210s

ma

• Antimatter gravity has to this day never been

investigated directly!

• WEP test

General relativity is a classical (non quantum) theory!

srvrbeae

r

mmGV

//21 1

• Tensor → “Newton”, always attractive

• Vector → repulsive between like charges

• Scalar → always attractive

The non-Newtonian terms could (almost) cancel out if a ≈ b

and v ≈ s , but would produce a striking effect on antimatter

Matter-matter:

0ba

matter-antimatter:

0 ba

[T. Goldman, M. Nieto Phys. Lett 112B 437-440 (1982)]

[ E. Fischbach, C. Talmadge “The search for Non Newtonian Gravity” Springer]









• Conclusion


The AD – Antiproton Decelerator

107 antiprotons every ~90 s

0.1 GeV/c

200 ns bunches

asacusa

alpha

Electron cooling

Stochastic cooling

[J. Y. Hémery & S. Maury, NPA 655 (1999) 345c]

[Proposed antimatter gravity measurement with an antihydrogen

beam. By AEGIS Proto Collaboration (A. Kellerbauer et al.). 2008.

6pp. Nucl.Instrum.Meth.B266:351-356,2008. ]

Goal: producing an horizontal beam of antihydrogen

And measuring its vertical deflection over a path of 1m.

1% precision is expected in the first phase.

AD

SID

E

p

5 Tesla Magnet

4K region

Cathing pbars from

AD

1Tesla Magnet

100mK region

Pbars cooling

Hbar prod.

Moire

deflect.

g-meas.

Positrons

source

Positrons

accumulator

The AEgIS apparatus

Positrons

Transfer

line

Trap scheme

Catching and cooling

Antiprotons from A.D.

Pbars cooling (100 mK region)

Antihydrogen production:

Moire deflectometerPs* production

(target + lasers)

Position sensitive

detector

Antihydrogen atoms are produced at temperature of

pbars prior to recombination !!!

B = 5 T

T = 4 K

B = 1 T

eHPsp**

Positrons and electrons

are in plasma regime

↓↓

Collective behaviour!

Catching pbars+

HV ONHV ONElectron plasma

108 e-

electron cooling (t ≈ 10 s)

B = 5 T

T = 4 K

> 104 pbars confined and cooled in the 4K trap

[1] S. L. Rolston and G. Gabrielse Cooling antiprotons in an ion trap Volume 44, Numbers 1-4 / March, 1989

[2] The ATHENA antihydrogen apparatus Nucl. Inst.Meth. Phys. Res. A 518, 679-711 (2004)

Antihydrogen production+

p

Cooling of antiprotons

Down to 100mK

The temperature of

Pbars here will determine

the temperature of

produced H-bar!

e+

Positrons transfer

and

diocotron jump on target

[J. Fajans et al., PHYS. REV. LETT. 82,22]

[J. R. Danielson, T. R. Weber, and C. M. Surko PHYS. OF PLASMAS 13, 123502 2006]

B = 1 T 100 mK

region

Beam formation and g meas.+

e+

p

n=1

n=3

6.0

5 e

V

0.7

5 e

V

n=35

nanoporous material

target (Ps conversion)

eHPsp**

Stark accelerator

[E. Vliegen & F. Merkt, J. Phys. B 39 (2006) L241]

Vh= 400 m/s

Vh= 600 m/s

Vh= 300 m/s

Vh= 250 m/s

x

counts

EnkF

2

3

• Δv of several 100 m/s within about 1 cm

• Electric fields: few 100 V/cm (limited by field

ionization)

• Already working with Rydberg hydrogen! [E. Vliegen & F. Merkt, J. Phys. B 39 (2006) L241]

The beam is produced using a

stark accelerator:

• H is in Rydberg state

• Interactions between electric

•dipole moment and

a non-uniform electric field:









• Conclusion


Diocotron off-axis jump of plasma:

• Off axis jump must be precise (θ,d)

• reproducible

• High efficiency (no particle loss)

• only small expansions of plasma are tolerable

This techniques has been studied by [1]. AEgIS requires to implement

it into a lower magnetic field and to different shape of plasma

Several tests have been performed in our apparatus

with electrons matching the condition of the AEgIS apparatus

Results will be presented in the following slides

[1] [J. R. Danielson, T. R. Weber, and C. M. Surko PHYS. OF PLASMAS 13, 123502 2006]

[J. Fajans et al., PHYS. REV. LETT. 82,22]

e+

Positrons confined

into the MP trap, are

in plasma regime and

have collective

behaviour!

N ≈ 107

n ≈ 108 e+/cm3

R,z ≈ mm

MCP

+

Phosphor

screen

electron source

Faraday cupB = 0.5 -2T

• Load electrons into the trap

• Applying rotating wall

• …

• Diagnostic on plasma

N = 108 Ne-

n = 108 e-/cm3

RP < 1 mm

Zp = 2 - 3 cm

Experimental setup

T=300K

P=10-10 mbar

Trap radious r = 7 mm

0

20

40

60

80

100

120

140

160

180

200

0 50 100 150 200 250

N 1

0 E

+6

T [s]

INFN Genova, Italy

C. Canali, C. Carraro, L. Di Noto,

D. Krasnický, V. Lagomarsino,

G. Manuzio, G. Testera, R. Vaccarone,

S. Zavatarelli

Electrons confined into the MP trap, are in plasma regime and have collective behaviour!

CCD

Diocotron excitation

B

cne

R

Rf

R

Rf

W

PE

W

PD

22

For a long plasma column (LP>>RP) the linear frequency of diocotron motion (mθ=1) is:

RP and RW are the plasma and the trap radius.

For large displacements a non linear shift in the frequency arise:

2

1

1

w

DNL

R

dff

There is a relationship between fNL and d

Bringing the plasma diocotron mode in resonance to

a certain frequency is equivalent to move it off axis to

a distance d.

Rw

d

2 4 6 8

30

20

10

10

20

30

0 20 40 60 80

30

20

10

10

20

30

Diocotron signal

f1 = 3 kHz t1 = 5 ms

f2 = 6 kHz t2 = 5 ms

f3 = 9 kHz t3 = 5 ms

Dump pulse trigger

(Plasma is ejected on the MCP)

Phase

difference

ΦPlasma enter

in autoresonance

regime

d = displacement from

trap center

θ = angle

θ

d

Diocotron

drive

2 4 6 8

30

20

10

10

20

30

Dump

Pulse trigger

Φ = 0

2 4 6 8

30

20

10

10

20

30

Dump

Pulse trigger

Φ = 270

2 4 6 8

30

20

10

10

20

30

Dump

Pulse trigger

Φ = 180

0

50

100

150

200

250

300

350

0 100 200 300 400

Pla

sma

angl

e [d

eg]

Diocotron Phase [deg]

The angle θ can be precisely controlled by

synchronizing

diocotron excitation signal and the dump pulse

θ

d

Ne = 0.8 108

n = 108 cm -3

Rp = 0.7 mm

-400

-300

-200

-100

0

100

200

300

400

-400 -200 0 200 400

0

100

200

300

400

500

600

700

800

900

1000

0 200 400 600 800 1000

B = 2T B = 0.5 T

12 kHz

(5.5 mm)

9 kHz

(2.5 mm)

6.5 kHz

(0.5 mm)

24 kHz

(5.0 mm)

20 kHz

(2.0 mm)

14 kHz

(0.6mm)

Radial displacement is controlled

by the driving frequency

The diocotron jump works at low field with

The desidered shape of plasma









• Conclusion


Cooling of antiprotons can be performed with several tecniques:

• Resistive cooling (electron plasma is cooled using a tuned circuit)[Lowell S. Brown and Gerald Gabrielse Rev. Mod. Phys. 58, 233–311 (1986)]

• Sympatetic cooling with negative ions (heavy negative ions are laser cooled and placed )[A. Kellerbauer & J. Walz, New J. Phys. 8 (2006) 45]

• Electron cooling (thermal equilibrium between antiprotons and electron plasma)[S.L. ROLSTON and G. GABRIELSE Hyperfine Interactions 44 (1988) 233-246]

4 K → 0.5 K

0.5 K → 0.1 K

→ 0.001 mK

100 mK ≈ 50 m/s pbarL C

pe-

In a magnetic field electrons radiate their cyclotron energy and they come into equilibrium with the

environment

At temperature lower than few Kelvin electron cooling procedure is limited for quantum reasons:

cC nE )(21

minimum cyclotron energy (n=0) is 0.5 K (100 µK) B=1T

Still the axial motion of electrons can be further cooled down:

An electron sees a real impedance R with a value proportional

to the Q of the tuned circuit: R = QωzL

L C

Resistive cooling:

R = QωzL

The resonant circuit has been tested @ 4K:

Tuned circuit:

L C 50 mK region of diluition cryostat

Resonant frequency 20 – 30 MHzLNA

Amplifier

@ 4- 10 K

Superconducting coil: Copper coil:

The Q-Factor of the circuit seems to be limited

by the capacitor, not by the coilA LNA cryogenic can be used

For a non destructive diagnostic on confined particles

Sympathetic cooling of antiprotons with negative ions:

[A. Kellerbauer & J. Walz, New J. Phys. 8 (2006) 45]

http://www.mpi-hd.mpg.de/kellerbauer/en/index.htm

X− /

ion plasma

Suggested by:

MPI-K, Heidelberg,

Germany

Sympathetic cooling antiprotons with negative ions:

Os− is the only known negative ion with transition suitable for laser cooling

The possibility of using Os- for indirect laser cooling is under investigation,

Some important milestones have been reached

[A. Kellerbauer & J. Walz, New J. Phys. 8 (2006) 45]

http://www.mpi-hd.mpg.de/kellerbauer/en/index.htm

Alban Kellerbauer

Arne Fischer

(grad student)

Ulrich Warring

(Ph.D. student)

Raoul Heyne

(grad student)

Marco Amoretti

(post-doc),

Jan Meier

(grad student)

Christoph Morhard

(Ph.D. student)

Carlo Canali

(post-doc)

[U. Warring et al., Phys. Rev. Lett. 102 (2009) 043001]

ν = 257.831190(30) THz

λ = 1162.74706(14) nm

σ0 = 2.5(7) 10−15 cm2

High-Resolution Laser Spectroscopy on the Negative Osmium Ion has been performed:

(factor 100 improvement)

187Os- 189Os-

The hyperfine structure of the bound–bound transition in two Os− isotopes with a non-zero nuclear spin has been

measured:

[A. Fischer, “Laser spectroscopy on the negative osmium ion,” Diploma thesis, University of Heidelberg (2009).

Phys. Rev. Lett. 104 (2010) 073004.

Using the knowledge of the ground and excited state angular momenta, the full energy level diagram in an

external magnetic field was calculated

[A. Fischer, “Laser spectroscopy on the negative osmium ion,” Diploma thesis, University of Heidelberg (2009).

Phys. Rev. Lett. 104 (2010) 073004.

This suggest a scheme for laser cooling

based on a double laser wavelenght:

Conclusions:

• AEgIS intend to measure the gravity acceleration of antihydrogen

This will be the first direct measurement of gravity on antimatter

• Several weel-estabilished techniques (experience of past

experiments), and some innovative scheme have to be tested or

implemented in AEgIS

Some experimental results on plasma manipulation have been shown

Some ideas about the cooling of antiprotons have been discussed

• The AEgIS apparatus is under construction

Thanks for your attention

http://aegis.web.cern.ch/

Documents

AE IS - Jyväskylän yliopisto · Particle, manipulation techniques in AE IS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy)C. Canali INFN sez. Genova (AEgIS coll.)