Thomas StöhlkerGSI and University of Heidelberg

STRONG FIELD ATOMIC PHYSICS AT GSI/FAIR:

STATUS AND OUTLOOK

Jena

Jülich

ParisGrenoble

DarmstadtCracowCaen

D. BanasG. BednarzC. BrandauS. GeyerA. GumberidzeS. HessR. MaertinR. ReuschlD. SierpowskiU. SpillmannS. TashenovM. TrassinelliS. TrotsenkoG. Weber

The Collaboration

GreenbeltMadison

Mainz Frankfurt

Lanzhou

Heidelberg

Theory: J. Eichler, S. Fritzsche, V. Shabaev, A. Surzhykov

Positive Continuum

Negative Energy Continuum

TransferExcitation Ionization

Free Pair Production

+ mc

- mc2

2

e+

e-

0

Intense Laser

HydrogenEK = -13.6 eV<E>= 1 • 1010 V/cm

Z = 1

Z = 92

H-like UraniumEK = -132 • 103 eV<E>= 1.8 • 1016 V/cm

Atomic Physics in Extremly Strong Coulomb Fields

Atomic Structure at High-Z

• bound state quantum electrodynamics (QED)

• effects of relativity on the atomic structure

• electron correlation in thepresence of strong fields

• dynamically induced strong field effectsub-attoseconds (10–22 s < t < 10–18s

• supercritical fields

1 10 20 30 40 50 60 70 80 90109

1010

1011

1012

1013

1014

1015

1016

1s

<E>

[V/c

m]

Nuclear Charge, Z

ApplicationsApplications• ion cooling techniques• storage and trapping techniques• laser and spectrometer development• photon, electron, ion detection techniques

DynamicsDynamics

• dynamically induced strong field effects,sub-attoseconds (10–22 s < t < 10–18s)

• correlated many body dynamics• elementary atomic processes at high Z• photon matter interaction, e.g. photon

polarization correlation

Positive Continuum

Negative Energy Continuum

TransferExcitation Ionization

Free Pair Production

+ mc

- mc2

2

e+

e-

0

StructureStructureStudiesStudies

• bound state quantum electrodynamics (QED)• nuclear effects on the atomic structure• effects of relativity on the atomic structure• electron correlation in strong fields• supercritical fields

Atomic Physics in Strong Coulomb Fields

Self energy Vacuum polarization

U92+ SE VP NS355.0 eV -88.6 eV 198.7 eV

∆Ε=α/π (αZ)4 F(αZ) mec2

Low Z-Regime: αZ << 1F(αZ): series expansion in αZ

High Z-Regime: αZ ≈ 1 F(αZ): series expansion in αZ not appropriate

Goal: ±1 eV

Bound-State QED: 1s Lamb Shift at High-Z

To proof the validity of QED at high-Z, a broad range of different experimental

approaches is needed

1s-Lamb shift g-factor

2s2p inHe-like

ions

two-electronQED

hyperfinestructure

Test of QED in the Strong Field Regime

massmeasurements

and ...

Production, Storage, and Cooling of HCI

Electron Cooling0.90 0.93 0.96 0.99 1.02 1.05 1.08 1.11

0.0

0.2

0.4

0.6

0.8

1.0

beam

inte

nsity

(arb

. uni

ts)

f / f0

uncooled beam

0.90 0.93 0.96 0.99 1.02 1.05 1.08 1.110.0

0.2

0.4

0.6

0.8

1.0

beam

inte

nsity

(arb

. uni

ts)

f / f0

uncooled beam electron cooled beam

∆p/p ~ 10-5

Storage Ring

Cooling in Storage Rings

electron coolingstochastic coolinglaser cooling

Cooling in Traps

resistive coolingevaporative coolinglaser coolingelectron cooling

Storing and Cooling ist the key for precision

Traps

Precision Spectroscopy @ the ESR Storage Ring

Injection Energy400 MeV/u

Experiment @ 4 MeV/u

dece

lera

tion

Injection Energy400 MeV/u

strippertarget

ESR

electron cooling and deceleration to 4 MeV/u

U91+

400

MeV

/u

coolerPenning

trap

experiments with particles

at restU91+

deceleratorlinac

SIS

UNILAC

6 keV/u

4 MeV/u

5 keV*q

strippertarget

ESR

electron cooling and deceleration to 4 MeV/u

U91+

400

MeV

/u

coolerPenning

trap

experiments with particles

at restU91+

deceleratorlinac

SIS

UNILAC

6 keV/u

4 MeV/u

5 keV*q

U73+

11.4 MeV/u

HITRAP Schematic Overview

~105 U92+ ions~105 U92+ ions

O. Kester et al.

1990 1992 1994 1996 1998 2000 2002420430440450460470480490500510520

Dec

eler

ated

Ions

: C

oole

r (ou

r exp

.)Year

Lam

b S

hift

[eV

]

U91+

Gas

jet

Coo

ler

Dec

eler

ated

Ions

: Jet

Theory

The 1s-LS in H-like Uranium

Test of Quantum Electrodynamics (1s-LS)

80 100 120 140 160 180 2000

20

40

60

80

100

120

140

coun

ts

photon energy [kev]

Lyα1

Lyα2

K-RR

1s Lamb shift

2p3/2

2p1/2

2s1/2

1s1/2

Lyα1 (E1)

Lyα2 (E1)M1

1s-Lamb Shift

Experiment: 459.8 eV ± 4.6 eV

Theory: 463.95 eV

A. GumberidzePRL 94, 223001 (2005)

Research HighlightsNature 435, 858-859

(16 June 2005)

The 1s-LS in H-like Uranium (Exp. at GSI)

Test of Quantum Electrodynamics (1s-LS)

80 100 120 140 160 180 2000

20

40

60

80

100

120

140

coun

ts

photon energy [kev]

Lyα1

Lyα2

K-RR

1s Lamb shift

2p3/2

2p1/2

2s1/2

1s1/2

Lyα1 (E1)

Lyα2 (E1)M1

10 20 40 60 80 10010-5

10-4

10-3

10-2

10-1

1s L

amb

Shi

ft , ∆

E /

Z4 [m

eV]

nuclear charge number, Z

2005

2000

19961991

SE

VP

nuclear size

Goal: Goal: AccuracyAccuracy of of betterbetter 1 1 eVeV forfor thethe LambLamb ShiftShift in in highhigh--ZZ oneone--electronelectron ionsions

higher order

What I left out !

• Dielectronic recombination(ESR/NESR: C. Brandau, C. Kozhuharov et al.,

• Accurate mass measurements(HITRAP: K. Blaum et al.)

• g-factor measurements with HCIs(HITRAP: W. Quint et al.,)

δm/m < 1x10-11 →δmc2 ≈ 2 eV →'weighing' of Lamb shift

low-Z: most accurate determination of the electron mass

medium-Z: fine-structure constant ahigh-Z: test of QED

as tool to study bound state QED and/or nuclear radii (rare isotopes)

Eta Carinae

Hydrogen:λ = 21.10608180988(2) cm τ = 10 7 years

Hyperfine Structure at High-Z

Hyperfine Structure at High-Z

Hyperfine Structure at High-Z

Hyperfine Structure

Very similar findings:

[Ho] Crespo Lopez-Urrutia et al., 1996[Re] Crespo Lopez-Urrutia et al., 1998[Pb] Seelig et al., 1998[Tl] Beiersdorfer et al., 2001

In the case of HFS, disagreementbetween

experiment and atomic structuretheory based on QED

Experimenton the HFS will be continuedin 2009 at the ESR, W. Noertershäuser et al.

• Conclusion–experiments on bound state QEDat high-Z is very important partof A

20 40 60 80 100 120 140 160

1E11

1E12

1E13

1E14

1E15

1E16

1E17

1E18

<E

> V/

cm

Nuclear Charge, Z20 40 60 80 100 120 140 160

1E11

1E12

1E13

1E14

1E15

1E16

1E17

1E18

<E

> V/

cm

Nuclear Charge, Z

1s

2s

2p1/2

Critical- and Supercritical Fields

U92+ → U => U91+ + MO-X-Ray...

as function of impact parameter

RequirementsDeceleration to About 6 MeV/u

107 Slow Extracted Ions Large Solid Angle X-Ray Detectors

Monolayer Target (Uranium)Position Sensitve Particle Detectors

negative

continuum

positive

continuum+m0c2

-m0c2

0

E

boundstates

1s Lamb Shift

2eQED for He-like ions

2s-2p transitionsin He- and Li-like heavy ions

hyperfine-structure

g-factor of boundelectrons

Experiments

Self Energy VacuumPolarization

Test of Bound-State QED at high-Z

Parity admixture

( ) ( )

3 2 10 el 5 0

3 10 0

2 1 4 sin 22 2

2 2

Fw

G NP SZ

E P E S

ρ γη

⎛ ⎞− Θ −⎜ ⎟⎝ ⎠=

−

65 10η −= ⋅

GF: Fermi constant,

N: neutron number,

Θw: Weinberg angleZ: proton numberρel: electric charge density

Parity Violation in Highly Charged IonsHelium-like Uranium

( )1 1 2 1 vE M E p+

( )10 1 ,2S s s ( )3

0 1 ,2P s p

( )31 1 ,2S s s

( )10 1 ,1S s s

2 1E

1010 sτ −≈1310 sτ −≈

M1

[1s2p3/2]1P1

[1s2p3/2]3P2

[1s2p1/2]3P1

[1s2p1/2]3P0

[1s2s1/2]3S1

[1s2s1/2]1S0

First observation of the ∆n=0 3P2 → 3S1transition in He-like uranium: Experiment at the ESR

Accuracy goal: 0.5 eV

4510 eV ?PNC

e-

e-

q

qZ

Relative measurementHe-like Li-like (well-known)

U90+β = 0.25794

∆E = ElabHe - Elab

Li

U89+β = 0.29558

X-ray energy

August 2007

preliminary

M. Trassinelli et al. (2008), in preparation for PRL

Merged Beams

Supercritical fieldsSupercritical fields

U92+U91+

< 5 MeV/uFormation of a Quasi-Molecule

E(r)2pπ

1sσ

timeW. GreinerGSI-Workshop 1996

E [keV] negative continuum

2D/3D Si(Li)-Detector for Compton Polarimetry

crystall size: 4'' x 4''

Si(Li) and Ge(i) based Compton

polarimeter

energy resolution – timing - 2D/3D position sensitivity – multihit

Si(Li) Si(Li)

Ge(i)

32x32 strips2 mm pitch

128x48 strips250µm and 1167µm

Application to high precision spectroscopy based on transmission spectrometer (50 to 100 keV)

Laboratory Laboratory AstrophysicsAstrophysics

Polarization Spectroscopy

Direct insight into celestial plasmas

Spectra provide knowledge of temperature, density, element abundance, etc.

XX--rayray emissionemissionstudiesstudies forfor ionsions in in

well well defineddefinedchargecharge--statesstates QQ

XX--rayray emissionemission of of hot hot plasmasplasmas producedproducedbyby intenseintense laserlaser and and

ionion beamsbeams

FeQ+

Crab nebula

Radiative processes: Main photon matter interaction processes exhibit distinct photon polarization features (Synchrotron Radiation, Bremsstrahlung, Recombination, Inverse Compton Scattering)

∆E

E∆+= 'ωω hhenergy recoil electron :E∆

hω

hω ´θ

ϕ

E

Polarization Measurement via Compton Scattering

0

30

60

90

120

150

180

210

240

270

300

330

ϕ

E

)cos θsin2'

'()'(21 2

c222

0 ϕωω

ωω

ωωσ

−+=Ω h

h

h

h

h

hrdd

Klein-Nishina equationLinearly polarized radiation

hωe-

θc

Si(Li) 2D-strip

-180 -135 -90 -45 0 45 90 135 1800

100

200

300

400

500

600

inte

nsity

azimuthal angle (φ)0 30 60 90 120 150 180

0,0

0,2

0,4

0,6

0,8

1,0

pola

rizat

ion

frac

tion

observation angle, θLAB(deg)

S. Hess et al.,2008(Poster II39)

Stored Ions (Z=Q)

Dipole Magnet

Gas Jet

Experiments at the Jet-Target Electron transferfrom the target atominto the HCI

Particle Counter(MWPC)

50 100 150 200 250 300 350

0

200

400

Lyα1 K-R

EC

8-RE

C

M-R

EC L-R

EC

Lyβ

Lyα2

coun

ts

photon energy (keV)

Coincidence

...ωZ

eZ1)(Q

Q

++→

++−

−+

h

Si(Li) 2D-strip

Ψion beam

E

S

Spin Polarized Ion Beams

for spin polarized ions, thepolarization plane and scattering plane are not equal for spin aligned ionbeams

predictions by A.Surzhykov et al., PRL 94, 203202 (2005)

control over the spin-polarization of storedions:required for EDM and PNC experiments

spin-polarized

Recombination: spin polarization of particles Recombination: spin polarization of particles (ion or electron beam)(ion or electron beam)

Simulation

ψ degree of beampolarization⇒

LaserLaser--Acceleration of Electrons Acceleration of Electrons

typical setup for electronlaser acceleration studies:

Nature 431 (Sept. 2004):3 groups report on laser accelerationof (low-emittance) electron beams with (quasi-monochromatic) 70-200 MeV

E.g. Ex-ray (360keV) = 4 · γ2(for 150MeV e-) · EPhoton(1eV)

x-ray pulse (fs)MeV electron beam

electron pulse∼50 MeV,

(energy spread (2 to 4%)

Laser pulse1 TW, τ = 50 fs, λ=800 nm

X-ray pulse~60 keV, ~10 psωh

10mrad divergence

laser Pulse

First phase of experiment• determination of x-ray background• optimization of x-ray signal, e.g.

laser intensity, target density, pulse duration

Second phase of experiment• determination of the x-ray polarization

Hard x-ray generation using Thomson scattering off laser accelerated electron bunches

Collaboration with the l'OASIS Group@LBNL(supported by NSF,DAAD)

Time Profile

High Intensity Laser PHELIX

• UNILAC ion beam: 5 MeV/u S15+

• heating laser: Phelix,15 ns, 150 J

Challenges and Challenges and OpportunitiesOpportunities• Heavy Highly Charged Ions• Relativistic Heavy Ions• Radioactive Nuclei• Antiprotons

I. Extreme Static Electromagnetic Fields

II. Extreme Dynamic Fields

III. Ultra-Slow and Trapped Antiprotons