Relativistic dynamics of (slow) highly-charged ions Stephan - - PowerPoint PPT Presentation

Relativistic dynamics of (slow) highly-charged ions

Thanks to: N.M. Kabachnik, A. Surzhykov, T. Stöhlker and GSI Atomic Physics Group

Stephan Fritzsche GSI Darmstadt & Oulu University Eisenach, 28th June 2010

electron-photon interaction electron-electron interaction

ultra-strong

I n t e n s e L a s e r

E ≈ 1 0 1 6 V / c m E ≈ 1 0 1 6 V / c m

Highly-charged ions provide a unique tool

• - for probing strong electro-magnetic fields

ultra-strong

I n t e n s e L a s e r

E ≈ 1 0 1 6 V / c m E ≈ 1 0 1 6 V / c m

Highly-charged ions provide a unique tool

• - for probing strong electro-magnetic fields

1990 1992 1994 1996 1998 2000 2002

420 430 440 450 460 470 480 490 500 510 520

Decelerated Ions: Cooler (our exp. )

Year Lamb Shift [eV]

U91+

Gasjet Cooler

Decelerated Ions: Jet

Theory

• A. Gumberidze et al., PRL 94 (2005) 223001

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

ultra-strong ultra-short

I n t e n s e L a s e r

 = 1

1−v/c

2

E ≈ 1 0 1 6 V / c m E ≈ 1 0 1 6 V / c m

t ≤

0 . 1 a s I ≈ 1 0 2 1 W / c m

2

t ≤

0 . 1 a s I ≈ 1 0 2 1 W / c m

2

In contrast to: few-cycle laser pulses

Highly-charged ions provide a unique tool

• - for probing strong electro-magnetic fields

decelerated ion beams, HITRAP

Relativistic dynamics of (slow) highly-charged ions

Thanks to: N.M. Kabachnik, A. Surzhykov, T. Stöhlker and GSI Atomic Physics Group

Stephan Fritzsche GSI Darmstadt & Oulu University Eisenach, 28th June 2010

electron-photon interaction electron-electron interaction Plan of this talk

Electron capture: angular correlations & polarization Multipole mixing in strong fields Two-step processes: Capture vs. excitation Atomic PNC: Two-photon processes Spectroscopy of (super-) heavy elements Conclusions

Electron capture by bare ions

• - angular correlation and polarization studies

total cross sections angular distributions

So far...

~ ∑

polarization∫d ∣M∣ 2

d  d  ~ ∑

polarization

∣M∣

2

Electron capture into bare high-Z ions

New directions ...

polarization Alignment studies

~ ∣M∣

2

No summation over polarization states !

total cross sections angular distributions

So far...

~ ∑

polarization∫d ∣M∣ 2

d  d  ~ ∑

polarization

∣M∣

2

Electron capture into bare high-Z ions

Multipole mixing of the radiation field

• - in the capture and decay of highly-charged ions

2p3/2 1s1/2 Lyman-α 1

Magnetic sublevel population of the residual ion can not be measured directly But: knowledge on population of excited ion state may be derived from the properties of subsequent decay

anisotropy parameter

U91+ Tp = 310 MeV/u

• J. Eichler et al. PRA 58 (1998) 2128

W ∝1  P2cos

• bservation angle (deg)

angular distribution (arb. units) beam energy (MeV/u)



• Th. Stöhlker et al. PRL 79 (1997) 3270

fitting

Capture into the 2p3/2 excited states of initially bare ions

2p3/2 1s1/2 Lyman-α 1

Magnetic sublevel population of the residual ion can not be measured directly But: knowledge on population of excited ion state may be derived from the properties of subsequent decay

anisotropy parameter

U91+ Tp = 310 MeV/u

• J. Eichler et al. PRA 58 (1998) 2128

W ∝1  P2cos

• bservation angle (deg)

angular distribution (arb. units) beam energy (MeV/u)



• Th. Stöhlker et al. PRL 79 (1997) 3270

fitting

Capture into the 2p3/2 excited states of initially bare ions

=1 2 b=±3/2−b=±1/2 b=±3/2b=±1/2



Theory:

alignment of the 2p3/2 state: relative sublevel | jb mb> population

W ∝1eff P2cos 

eff =1 2  ±3/2− ±1/2  ±3/2 ±1/2



f E1 , M2



alignment parameter structure function

f E1 , M2∝123 〈∣M2∣〉 〈∣E1∣〉

effective anisotropy parameter 2p3/2 1s1/2

E1 M2

Double slit screen

P12 = |φ1 + φ2|2 P1 ~ |φ |2

Effective anisotropy parameter: Multipole contributions

W ∝1eff P2cos 

eff =1 2  ±3/2− ±1/2  ±3/2 ±1/2



f E1 , M2



alignment parameter structure function

f E1 , M2∝123 〈∣M2∣〉 〈∣E1∣〉

effective anisotropy parameter 2p3/2 1s1/2

E1 M2

Effective anisotropy parameter: Multipole contributions

W ∝1eff P2cos 

eff =1 2  ±3/2− ±1/2  ±3/2 ±1/2



f E1 , M2



alignment parameter structure function

f E1 , M2∝123 〈∣M2∣〉 〈∣E1∣〉

effective anisotropy parameter In contrast, contributions to decay rates appear additive:

 M2 tot ∝ ∣〈∣M2∣〉∣

2

∣〈∣E1∣〉∣

2

∝ 0.008

even for U91+

2p3/2 1s1/2

E1 M2

Effective anisotropy parameter: Multipole contributions

Dynamical alignment studies enables one to explore magnetic interactions in the bound-bound transitions in H-like ions !

U91+ Tp = 310 MeV/u

W ∝1eff P2cos 

fitti ng

• bservation angle (deg)

angular distribution (arb. units)

eff

beam energy (MeV/u) effective anisotropy parameter

• A. Surzhykov et al. PRL 88 (2002) 153001

E1-M2 multipole mixing: Alignment of the 2p3/2 state

Normal (independent) measurement Coincidence measurement

?

W RR , =

Photon-photon correlation functions:

Two-photon coincidence studies

Normal (independent) measurement Coincidence measurement Photon-photon correlation functions:

Two-photon coincidence studies

• bservation angle θRR

d i f f e r e n t i a l a l i g n m e n t

U91+

a n g u l a r d i s t r i b u t i

• n
• bservation angle θ

θRR = 0 deg θRR = 15 deg θRR = 90 deg θRR = 0 deg θRR = 15 deg θRR = 90 deg Lengthy derivation in the framework

• f the density matrix theory.

W RR , ∝ 1 4 5 ∑

q

A2qRRY 2q

X-ray polarimetry for HCI

• - exploring a new `dimension' in the electron-photon interaction

K-shell capture or subsequent decay

U92+ ion beam

gas jet

• S. Tachenov, G. Weber, T. Stöhlker, a.o.

position sensitive detector

recombination photoionization

Linear polarization of emitted x-ray photons

• - theoretical expectation

Linear polarization is described in the plane, perpendicular to the photon momentum.

• nly 2 (Stokes) parameters are required !

P L=P 1

2P 2 2

cos2= P 1 P L

electric dipole approximation

recombination photoionization

W PI ∝ sin2 cos2 P 1=I 0−I 90 I 0I 90

photoelectron angular distribution: photoelectrons are emitted predominantly within the plane of the electric field

Stobbe, Ann. Phys. 5 (1930) 661

electric dipole approximation

Linear polarization of emitted x-ray photons

• - Statistical characteristics for photon ensembles

recombination photoionization electric dipole approximation

Linear polarization of emitted x-ray photons

• - Statistical characteristics for photon ensembles

Relativistic effects decrease the linear polarization ! Cross-over behaviour !!

• A. Surzhykov et al, PLA 289 (2001) 213
• J. Eichler et al, PRA 65 (2002) 052716

U92+ 100 MeV/u 300 MeV/u 500 MeV/u 800 MeV/u

• F. Sauter, Ann. Phys. 9 (1931) 217
• U. Fano, Phys. Rev. 116 (1959) 1156

Linear polarization of emitted x-ray photons: Applications

• - Diagnostics of highly-charged ion beams

Proposal: to use REC linear polarization

as a probe for ion spin polarization. Established theory from the “polarization transfer” in atomic photoionization.

• U. Fano et al., Phys. Rev. 116 (1959) 1147;
• R. Pratt et al., Phys. Rev. 134 (1964) A916.

Linear polarization of emitted x-ray photons: Applications

• - Diagnostics of highly-charged ion beams

Proposal: to use REC linear polarization

as a probe for ion spin polarization. Established theory from the “polarization transfer” in atomic photoionization. Calculations performed for the REC into (initially) hydrogen-like bismuth Bi82+ ions (I = 9/2) for the energy Tp = 420 MeV/u.

• U. Fano et al., Phys. Rev. 116 (1959) 1147;
• R. Pratt et al., Phys. Rev. 134 (1964) A916.

λF = 0.0 λF = 0.3 λF = 0.7 λF = 1.0

P 1= I 0−I 90 I 0I 90 P 2=I 45−I 135 I 45I 135

Linear polarization of emitted x-ray photons: Applications

• - Diagnostics of highly-charged ion beams

Proposal: to use REC linear polarization

as a probe for ion spin polarization. Established theory from the “polarization transfer” in atomic photoionization. Calculations performed for the REC into (initially) hydrogen-like bismuth Bi82+ ions (I = 9/2) for the energy Tp = 420 MeV/u.

• U. Fano et al., Phys. Rev. 116 (1959) 1147;
• R. Pratt et al., Phys. Rev. 134 (1964) A916.

tan2= P 2 P1

direction of polarization

• A. Surzhykov et al., Phys. Rev. Lett. 94 (2005) 203202

Linear polarization of emitted x-ray photons: Applications

• - Diagnostics of highly-charged ion beams

Proposal: to use REC linear polarization

as a probe for ion spin polarization. Established theory from the “polarization transfer” in atomic photoionization. Calculations performed for the REC into (initially) hydrogen-like bismuth Bi82+ ions (I = 9/2) for the energy Tp = 420 MeV/u.

• U. Fano et al., Phys. Rev. 116 (1959) 1147;
• R. Pratt et al., Phys. Rev. 134 (1964) A916.

φ

tan 2 = P2 P1 ~ F I −1/2 I 1/2

Rotation angle φ provides information on the degree of ion polarization !

• S. Tashenov et al., PRL 97 (2006) 223202;
• A. Surzhykov et al., PRL 94 (2005) 203202.

Two-step processes: Capture vs. excitation

• - Do we get more by following the

dynamics of the ions ?

(initially) bare ion (initially) H-like ion

Lyman-α vs. K-α emission from high-Z ions

(initially) bare ion

U92+ Tp = 309 MeV/u

Ly-α1 is strongly anisotropic

• X. Ma et al, PRA 68 (2003) 042712.

U91+ Tp = 102 MeV/u

K-α1 is isotropic

(initially) H-like ion

Lyman-α vs. K-α emission from high-Z ions

(initially) bare ion

U91+ Tp = 102 MeV/u U92+ Tp = 309 MeV/u

Ly-a1 is strongly anisotropic

K-α1 is isotropic W E1~1 1

2 A2J =1P 2cos

W M2~1− 5 14 A2J =2P 2cos 

E1: M2:

(initially) H-like ion

• X. Ma et al, PRA 68 (2003) 042712.

K-α decay of highly-charged ions

• - angular distribution as „observed“ in experiment

W K 1~N J =1W E1N J =2W M2 =1N J =1 1

2 A2 J =1−N J =2

5 14 A2 J =2 P2cos

N J =1 , N J =2

relative populations of J=1, 2 states

N J =1=N J =2=1 2

N J =1= 3 8 N J =2= 5 8

Calculations have been done for L-REC

• f U91+ with Tp = 100 MeV/u

E1+M2 E1 only

• A. Surzhykov et al., PRA 73 (2006) 032716.

K-α decay of highly-charged ions

• - for 220 MeV/u U90+ ions following REC

W K 1~N J =1W E1N J =2W M2 =1N J =1 1

2 A2 J =1−N J =2

5 14 A2 J =2 P2cos

• A. Surzhykov et al., PRA 73 (2006) 032716.

E1 M2 (70 %) E1 (30 %)

Relative populations of the J = 1, 2 levels following REC (IPM model): By taking into account 3P2 -> 3S1 channel: N J =1 N J =2 =3 5 N J =1 N J =2 =6 7



N J =1−N J =2 N J =1N J =2theory ≈ −0.08

K-α decay of highly-charged ions

• - following the Coulomb excitation of the projectiles

W K 1~N J =1W E1N J =2W M2 =1N J =1 1

2 A2 J =1−N J =2

5 14 A2 J =2 P2cos

• A. Surzhykov et al., PRA 73 (2006) 032716.

excitation of He-like U90+ ion

Excited states of He-like heavy ions can be produced

also by the Coulomb excitation of the projectile in the field

• f target atoms.

Experiments were already performed at the GSI storage ring for He-like uranium ions U90+.

Strong anisotropy of the subsequent Kα1 radiation has

been observed!

K-α decay of highly-charged ions

• - following the Coulomb excitation of the projectiles

E1 M2 (70 %) E1 (30 %)

W K 1~N J =1W E1N J =2W M2 =1N J =1 1

2 A2 J =1−N J =2

5 14 A2 J =2 P2cos

N J =1 , N J =2

relative populations of J=1, 2 states

Tp = 217 MeV/u

Angular distribution results dominant- ly from the decay of the J=1 level. Role of electron-electron interactions still unexplored.

Atomic parity non-conservation processes

• - Two-photon processes for HCI

e - e - q q e - e - q q e - e - q q Z e - e - q q e - e - q q Z

γ

Exchange of Z-boson leads to the mixing

• f atomic levels with different parities.

E n e r g y

s ( + ) p ( - )

PNC studies with heavy, few-electron ions

• - enhancement of parity and time-reversal violating interactions

Helium-like uranium U90+ is a perfect candidate for PNC studies: Simple system (only 2 electrons) Large electron-nucleus overlap Small 21S0-23P0 energy splitting Still many open questions: How big is the 21S0-23P0 energy splitting? How strong laser fields do we need? What is the role of e-e interactions?

8 0 8 2 8 4 8 6 8 8 9 0 9 2 9 4

• 8
• 6
• 4
• 2

2 4 6 8

n u c le a r c h a r g e , Z

∆ E ( e V )

8 0 8 2 8 4 8 6 8 8 9 0 9 2 9 4

• 8
• 6
• 4
• 2

2 4 6 8

n u c le a r c h a r g e , Z

∆ E ( e V )

Analysis and interpretation of optical and x-ray spectra (astro physics) Diagnostics of astro physical and laboratory plasmas Development of UV/EUV light sources and lithograhpy Frequency standards and atomic clocks Spectroscopy on heavy and superheavy elements (actinides, transactinides) Isotope shifts and hyperfine structures Nonradiative (inner-shell) transitions and autoionization Ion recombination and photon emission Multi-photon processes ... ... „Complete experiments“ Parity nonconservation (PNC) Search for electric dipole moments

There is a need for accurate many-electron calculations ! „ „many but not so many but not so accurate“ accurate“

Lr No Md Fm Es

Atomic Structure unknown !

Lr

Backe, Lauth, Sewtz (Mainz)

Atomic Physics : Atomic Structure Ionization Potentials Nuclear Physics : Nuclear Spins, Moments

Atomic Levels Theoretical challenges:

strong relativistic and QED effects

systems with open d- and f-shells many overlapping and nearly degenerate configurations large number of electron

Spectroscopy of heavy and super-heavy elements

Atomic Physics: Atomic Structure Ionization potentials Nuclear Physics: Nuclear spins Moments Changes of charge radii

Scan Distance : 1800 cm-1

• M. Sewtz et al., Phys. Rev. Lett. 90 (2003) 163002

Theoretical request: Energies, lifetimes, transition rates

5f12 7s 7p, Jp = 6-, 5 5G6,5o ES : 5f12 7s 7p, Jp = 6-, 5-,7- 3H6,5,7o (?)

Breeding in High Flux Reactors NFm< 1012; 255Fm; t1/2= 20.1 h Determination of hfs and isotope shifts

Optical spectroscopy of atomic Fermium (Z = 100)

First observation and classification of atomic levels

Ground-state configuration:

[Rn] 5f14 7s2

Low-lying excitations:

[Rn] 5f14 7s 7p

5f13 6d 7s2 5f14 6d 7s 5f14 7s 8s 5f13 7s2 7p }

2 ... 5 eV

• M. Sewtz, W. Lauth et al., private commun. (2005)
• S. Fritzsche, EJP D33, 15 (2005)

Experimental proposal: Optical spectroscopy of nobelium (Z=102)

No

5f14 7s2

• pen 5f shell

6d shell 7p shell

Configuration interaction

3P1 1P1

Target Wheel Quadrupole Triplet Condenser Plates for Electric Field Dipole Magnets Beam Dump Quadrupole Triplet

Buffer Gas Cell Laser

254No Beam

RCC: Eliav et al.., Phys. Rev. A52 (1995) 291; DFT: Vosko & Chevary, J. Phys. B26 (1993) 873

Zhou & Froese Fischer., Phys. Rev. Lett. 88 (2002) 183001.

Low-lying resonances of (super-) heavy elements

... for lutetium (Z=71) and lawrencium (Z=103)

Good accuracy of the (atomic) energies is a Good accuracy of the (atomic) energies is a necessary, but not a sufficient criterion ! necessary, but not a sufficient criterion !

Zhou & Froese Fischer., Phys. Rev. Lett. 88 (2002) 183001

Low-lying resonances of (super-) heavy elements

... oscillator strengths in different gauges

RATIP

Relativistic Atomic Transition and Ionization Properties

(CPC library) Relativistic CI wave functions including QED estimates and mass polarization

RELCI, CPC 148 (2002) 103

LSJ spectroscopic notation from jj-coupled computations

LSJ, CPC 157 (2003) 239

Auger rates, angular distribu- tions and spin polarization; level widths

AUGER

Photoionization cross sect- ions and (non-dipole) angular parameters

PHOTO

Radiative and dielectronic recombination; angle-angle correlations ...

• S. Fritzsche, JESRP 114-116 (2001) 1155; Phys. Scr. T100 (2002) 46

Many-electron basis (wave function expansions)

Construction and classification of N-particle Hilbert spaces Shell model: Systematically enlarged CSF basis Interactions Dirac-Coulomb Hamiltonian Breit interactions + QED Electron continuum; scattering phases Coherence transfer and Rydberg dynamics

P J M  = ∑

r nc

cr∣r P J M 〉

RATIP

Relativistic Atomic Transition and Ionization Properties

(CPC library) Relativistic CI wave functions including QED estimates and mass polarization

RELCI, CPC 148 (2002) 103

LSJ spectroscopic notation from jj-coupled computations

LSJ, CPC 157 (2003) 239

Auger rates, angular distribu- tions and spin polarization; level widths

AUGER

Photoionization cross sect- ions and (non-dipole) angular parameters

PHOTO

Radiative and dielectronic recombination; angle-angle correlations ...

• S. Fritzsche, JESRP 114-116 (2001) 1155; Phys. Scr. T100 (2002) 46

Many-electron basis (wave function expansions)

Construction and classification of N-particle Hilbert spaces Shell model: Systematically enlarged CSF basis Interactions Dirac-Coulomb Hamiltonian Breit interactions + QED Electron continuum; scattering phases Coherence transfer and Rydberg dynamics

P J M  = ∑

r nc

cr∣r P J M 〉

U t i l i z e d i n m

• r

e t h a n 1 3 c a s e s t u d i e s d u r i n g t h e l a s t d e c a d e ; U t i l i z e d i n m

• r

e t h a n 1 3 c a s e s t u d i e s d u r i n g t h e l a s t d e c a d e ;

the offer the offer

t

• c
• n

s i d e r

• t

h e r s y s t e m s t

• c
• n

s i d e r

• t

h e r s y s t e m s . . . a n d p r

• p

e r t i e s . . . a n d p r

• p

e r t i e s

HFS & Isotope shift measurements for Os-

AG A. Kellerbauer et al. MPIK Heidelberg

J = 7/2 Jg = 9/2

J = 5/2 J = 3/2 Je

Os Os−

(eV)

0.50 1.00 1.50 2.00

Typical spectrum 192Os-:

Signal: Neutral atoms as function

• f laser frequency

⇒ ν = 257.831190(30) THz λ = 1162.74706(14) nm

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

Typical spectrum 192Os-:

Signal: Neutral atoms as function

• f laser frequency

Transition for all stable isotopes:

⇒ ν = 257.831190(30) THz λ = 1162.74706(14) nm

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

192A′/(192− A′)δ<r2

1 9 2 A′ / ( 1 9 2 −A′ ) δv

( T H z u ) −1600 −1300 −1200 −1400 −1500 −1100 −21 −20 −19 −18 −16 −15 −17

νcenter - 257892166 (MHz) c

• u

n t s two-photon detachment (x10) electric-field detachment

• 75
• 50
• 25

25 50 75 10000 20000 30000 40000 50000

MSMS = 2(11) THz u F = 16(9) GHz fm−2

p r e l i m i n a r y p r e l i m i n a r y

M NMS =ν0 me 1u =0.14 THz u

MSMS = 4.9 THz u F = 12.4 GHz fm−2 Experiment: Theory:

• A. Fischer et al., Phys. Rev. Lett. 104 (2010) 073004

HFS & Isotope shift measurements for Os-

AG A. Kellerbauer et al. MPIK Heidelberg

Atomic and heavy-ion theory @ SPARC collaboration

• - Recent developments and progress

Key topics of this collaboration:

Test of quantum electrodynamics in strong fields for light and high-Z ions ... two-times Green's functions; 2-photon, 3-photon (??) diagrams; differences with experiment

especially for the HFS; systematic QED approach in the MBPT framework

Collision & capture dynamics in strong fields at relativistic energies ... U28+ electron loss; few-body dynamics; polarization effects; multi-electron processes Atomic physics techniques applied to nuclear physics Multi-photon processes Antiproton physics Test of fundamental interactions and symmetries beside of QED Interaction of ions with intensive (laser) light ... dynamics in strong fields, high-harmonics generation

GSI

Atomic and heavy-ion theory @ SPARC collaboration

• - Recent developments and progress

Key topics of this collaboration:

Test of quantum electrodynamics in strong fields for light and high-Z ions ... two-times Green's functions; 2-photon, 3-photon (??) diagrams; differences with experiment

especially for the HFS; systematic QED approach in the MBPT framework

Collision & capture dynamics in strong fields at relativistic energies ... U28+ electron loss; few-body dynamics; polarization effects; multi-electron processes Atomic physics techniques applied to nuclear physics Multi-photon processes Antiproton physics Test of fundamental interactions and symmetries beside of QED Interaction of ions with intensive (laser) light ... dynamics in strong fields, high-harmonics generation

GSI

  f =  S  i  S



 S

• scattering operator

Initial state Final state

t −∞  i t ∞   f

〈1...m∣  f∣' 1...' m〉= ∑

1,2...

〈1...n∣ i∣' 1...' n〉〈1...n∣ R∣1...n〉〈' 1...' n∣ R∣' 1...' n〉



transition amplitudes initial-state density matrix

 P=∣∣

W =Tr   P   f = ∑

1...m

〈1...m∣ P   f ∣1...m〉

Measurement of physical properties:

'detector operator' describes the experimental setup:

probability to get a 'click' at the detectors:

Time-independent density matrix theory

  f =  S  i  S



 S

• scattering operator

Initial state Final state

t −∞  i t ∞   f

Time-independent density matrix theory

Using the density matrix, the system can be accompanied through several steps

• f the interaction which may lead to the emission of photons, electrons, ...

Great advantage ! Great advantage !

Weak-field photoexcitation and ionization:

cross sections, angular distributions & spin polarization, `complete experiments', ...;

for example: single-photon double ionization

A

A+ A++ He (Schneider and Rost, 2003)

Different mechanisms: shake-off, knock-out

He (Briggs and Schmidt, 2000)

Weak- vs. strong-field (light-matter) interactions

D

• m

a i n

• f

p r e c i s i

• n

p h y s i c s

Role of e-e correlations; parity and time-reversal violating interactions.

Current interests and challenges

Atomic processes and multipole mixing in strong fields Multi-electron coincidences (magnetic bottle) Second-order emission processes Creation and control of entangled photon pairs Parity non-conservation and time-reversal violation Studying fundamental constants (time variations, ...)

Ion-Atom Stöße

Z = 92 Z = 1

1 10 20 30 40 50 60 70 80 90 109 10

10

10

10

10

10

10

1s

<E> [V/cm] Nuclear Charge, Z

schnelle Stöße

„Einteilchenbild“

langsame Stöße

„Vielteilchenbild“

Hochgeladene Ionen sind sehr gut geeignet, um die elementaren Prozesse in (extrem) starken Feldern zu verstehen. Besseres Verständnis der Vielteilchendynamik erforderlich. Verstärkung des REC bei langsamen Ionen (!) Resonante (dielektronische) Rekombination. Abbremsen und Einfang in Fallen. Wichtig für Ionen-Oberflächen Prozesse. ... g = 1 g = 5

Ionen sind variabel:

Feldstärke Zahl der Elektronen Zeitskala

Supercritical fields in ion-atom collisions

Z~ 173

strong spin-orbit splitting; swapped `level order'

Fricke & Soff (1977)

Processes during the collision: excitation into higher shells

ionization (δ-electrons) MO radiation characteristic x-rays

Mokler & Liesen (1982)

multiple charged ion neutral target

negative ion source laser

Measurement principle:

• Laser frequency is scanned around transition

frequency

• Excited state is detached by electric field

Neutrals detected on forward MCP

mass separation negative ion source

J = 7/2 Jg = 9/2

J = 5/2 J = 3/2 Je

Os Os−

(eV)

0.50 1.00 1.50 2.00

Laser spectroscopy of Os-

@ MPI-K in Heidelberg (A. Kellerbauer et al.)

Measurement principle:

Laser frequency is scanned around transition frequency Excited state is detached by electric field Neutrals detected on forward MCP

SPARC-Collaboration @ FAIR

Stored and Cooled

Highly-Charged Ions and Exotic Nuclei

from Rest to Relativistic Energies Intense Beams of Radioactive Isotopes Virtual Photon Sources at X- and γ-Ray Energies XUV Energies via Lorentz Boost of optical wavelengths

... with Novel Instrumentation

Ultracold Electron-Beam Target

High Resolution X-Ray and Electron Spectrometers In-Ring Recoil Momentum Microscope Highly Intense Laser Beams Traps

SIS100/300 High Energy Cave New Experimental Storage Ring FLAIR

1x1012 1/s for U28+at 1 GeV/u 90 GeV protons 34 GeV/u U92+

ion beam

gas jet

• S. Tachenov/T. Stöhlker (2004)

position sensitive detector

Polarization of the K-shell REC photons

Compton effect: Klein-Nishina formula

d  d  ∝ ℏ ℏ'  ℏ' ℏ −2sin2 cos2

polarization dependence

ℏ  ℏ '

K-shell U92+