IAEA Tech Meeting: Uncertainty Assessment and Benchmark Experiments onAtomic and Molecular Data for Fusion Applications
Vienna, 12-16 September 2016
Andreas Wolf
Storage-Ring Merged Beams forElectron-Ion Collision Studies
Method
Results: Open 4f-shell tungsten ions, HCl+
Developments: Cryogenic storage ring
Max-Planck-Institut für Kernphysik, Heidelberg, Germany
http://www.mpi-hd.mpg.de/ion-storage
Scattering and inelastic collisions with charged-particle beams
Atomic/molecular gas
Ion–molecule (atom) charge exchangeCrossed-beams electron impact
Low-energy electron scattering
Low-energyelectron source
Atomic/molecular gas
Merged-beams electron impact
http://www.mpi-hd.mpg.de/ion-storage
Scattering and inelastic collisions with charged-particle beams
Atomic/molecular gas
Ion–molecule (atom) charge exchangeCrossed-beams electron impact
Low-energy electron scattering
Low-energyelectron source
Atomic/molecular gas
Merged-beams electron impact Down to zero collision energy
Narrow energy spread
Extended overlap
http://www.mpi-hd.mpg.de/ion-storage
Ion beam(in storage ring)
Overlap zoneInelastic collisions
Merged-beams electron ion collisions
Velocity-matched electron beamCollision energy: (v
e − v
i )2E
d = ½ m
e
~ 1 meV … keVWide scan range:
http://www.mpi-hd.mpg.de/ion-storage
Ion beam(in storage ring)
Overlap zoneInelastic collisions
Merged-beams electron ion collisions
Velocity-matched electron beamCollision energy: (v
e − v
i )2E
d = ½ m
e
~ 1 meV … keVWide scan range:
Charge changing reaction(photo-recombination)
Products:
Xq+ + e− → X(q−1)+ + γ
http://www.mpi-hd.mpg.de/ion-storage
Ion beam(in storage ring)
Overlap zoneInelastic collisions
Merged-beams electron ion collisions
Velocity-matched electron beamCollision energy: (v
e − v
i )2E
d = ½ m
e
~ 1 meV … keVWide scan range:
- Counting- Momentum measurement (time + position)- Coincidence measurements
Charge changing reaction(photo-recombination)
Products:
Fragmentation(dissociative recombination)
AB+ + e− → A + B + ε
Xq+ + e− → X(q−1)+ + γ
http://www.mpi-hd.mpg.de/ion-storage
Ion beam(in storage ring)
Overlap zoneInelastic collisions
Merged-beams electron ion collisions
Velocity-matched electron beamCollision energy: (v
e − v
i )2E
d = ½ m
e
~ 1 meV … keV
- Fragment mass identification
Wide scan range:
Fragments keep (approx.) the beam velocity v
i
→ Laboratory kinetic energyof fragment f:
Ef = ½ M
f v
i2
- Counting- Momentum measurement (time + position)- Coincidence measurements
Fragmentation(dissociative recombination)
Charge changing reaction(photo-recombination)
Products:
AB+ + e− → A + B + ε
Xq+ + e− → X(q−1)+ + γ
http://www.mpi-hd.mpg.de/ion-storage
Ion storage ringTSR
Molecularion beam
Electronbeam
Fragment detectors
Storage ring merged beams experiments
1988 to 2012
Max-Planck-Institutfür Kernphysik
Tandem accelerator (~ 10 MeV·q )
Molecule Van-de-Graaff (~ 1...2 MeV)
http://www.mpi-hd.mpg.de/ion-storage
Ion storage ringTSR
Molecularion beam
Electronbeam
Fragment detectors
- Store and phase-space cool molecular ion beam- Reduce/control internal excitation of molecular ions (T
env = 300 K)
- Cold electrons (Te ~ 10 K) – vary collision energy of electrons
- Neutral fragment detection: ratesproduct momentaproduct masses
Storage ring merged beams experiments
1988 to 2012
Max-Planck-Institutfür Kernphysik
Tandem accelerator (~ 10 MeV·q )
Molecule Van-de-Graaff (~ 1...2 MeV)
http://www.mpi-hd.mpg.de/ion-storage
Iron ion dielectronic recombination
F-like Fe17+
Feq+ + e → (Fe(q−1)+)** → (Fe(q−1)+)* + γ
2s22p5 (2P3/2
) → 2s2p6 nℓ
C-like Fe20+
2s22p2 (3P0) → 2s2p3 (SL
J) nℓ
→ 2s22p5 (2P1/2
) nℓ
D. Savin et al., Astrophys. J. Lett. 489, L115 (1997) D. Savin et al., Astrophys. J. Suppl. 147, 421 (2003)
Theory: T. Gorczyca et al., N. Badnell et al.
[ → 2s22p2 (SLJ) nℓ ]
http://www.mpi-hd.mpg.de/ion-storage
0.1 1 10 100
0.1
1
10
100
Unpublished
Badnell, JPB (2006)
Badnell, APJ (2006)
mod.by Netzer,APJ (2004)
Arnaud & Raymond,APJ (1992)
Experiment Theory
collisionally-ionized
Fe13+
Rec
om
bin
atio
n r
ate
co
eff.
(1
0-1
0 cm
3 s-1)
Electron temperature (eV)
photo-ionized
Fe7+
Fe8+
E. W. Schmidt et al., Astrophys. J. Lett. 641, L157 (2006)
Al-like Fe13+
3s23p (2P1/2
)
→ 3s22p (2P3/2
) nℓ
→ 3s3p2 nℓ
Compiled byS. Schippers
Iron ion dielectronic recombination
Derived thermal plasma rate coefficients
http://www.mpi-hd.mpg.de/ion-storage
Tungsten ions: merged beams rate coefficientsS. Schippers et al., PRA 83, 012711 (2011)
N. Badnell et al., PRA 85, 052716 (2012)
C. Krantz et al., J. Phys. B Topical Review(JPB acceptedaper link 2016)
Intermediate coupling calculation
Radiative recombination
Fully partitioned (statistical) calculation
Xe-like W20+
4d10 4f8 (7F6)
→ 4d9 4f9 nℓ
→ 4d10 4f9 5d nℓ
→ 4d10 4f9 5g nℓ
→ 4d10 4f8 (f.s.) nℓ
(0 … 30 eV)
W20+ [Kr]4d104f8
http://www.mpi-hd.mpg.de/ion-storage
Tungsten ions: merged beams rate coefficientsW18+ [Kr]4d104f10
W19+ [Kr]4d104f9
W20+ [Kr]4d104f8
W21+ [Kr]4d104f7
S. Schippers et al., PRA 83, 012711 (2011)
K. Spruck et al., PRA 90, 032715 (2014)
N. Badnell et al., PRA 93, 052703 (2016)
K. Spruck, Thesis,Univ. of Giessen, 2015
N. Badnell et al., PRA 85, 052716 (2012)
C. Krantz et al., J. Phys. B Topical Review(JPB acceptedpaper link)
Stat. theor.V. A. Dzuba et al., PRA 86, 022714(2012).
~37%accuracy(90% conf.)incl. non-detectionof n > 69
http://www.mpi-hd.mpg.de/ion-storage
Tungsten ions: plasma recombination rate constantsS. Schippers et al., PRA 83, 012711 (2011)
K. Spruck et al., PRA 90, 032715 (2014)
N. Badnell et al., PRA 93, 052703 (2016)
N. Badnell et al., PRA 85, 052716 (2012)
C. Krantz et al., J. Phys. B Topical Review(JPB acceptedpaper link)
~37%accuracy(90% conf.)@150 eV
K. Spruck, Thesis,Univ. of Giessen, 2015
W18+ [Kr]4d104f10
W19+ [Kr]4d104f9
W20+ [Kr]4d104f8
W21+ [Kr]4d104f7
http://www.mpi-hd.mpg.de/ion-storage
Tungsten ions: excited ionic states
kBT = 560 eV
(for ion velocity in stripping target ~10 MeV W carbide anions)
+ 2468 other levels τ < 10 ms
W19+ [Kr]4d104f9 and 4d104f8 5s
Metastable levels
K. Spruck, Thesis,Univ. of Giessen, 2015
W19+ [Kr]4d104f9
Measurementtime in TSR
Storage time (s)
Fra
ctio
nal
leve
l po
pu
lati
on
http://www.mpi-hd.mpg.de/ion-storage
Absolute normalization: the lifetime method
SH+ n
e ~ 3 × 106 cm−3
W18+ n
e ~ 1 × 107 cm−3
electronsoff
electronson
electronsoff
electrons on
Detuning energy Ed = 0
Electron induced loss rate r
Overlap fraction Le/C
Electron density ne
Reaction rate constantα = r /(n
e · overlap fraction)
H. B. Pedersen, Phys. Rev. A 72, 012712 (2005)O. Novotný, Astrophys. J. 777, 54 (2013)
K. Spruck et al., PRA 90, 032715 (2014)
A. Becker, Thesis,Univ. of Heidelberg, 2016
http://www.mpi-hd.mpg.de/ion-storage
Molecular recombination measurements: Analysis
Calibration:Lifetime method
Merged-beams rate coefficient signal
O. Novotný, Astrophys. J. 777, 54 (2013)HCl+ + e → H + Cl + εkin
http://www.mpi-hd.mpg.de/ion-storage
Molecular recombination measurements: Analysis
Effectiveenergy distribution
Intrinsic electron velocitydistribution
Overlap geometry
Binned signal contributions(fitted cross section values)
O. Novotný, Astrophys. J. 777, 54 (2013)
Tail frommerging geometry
HCl+ + e → H + Cl + εkin
Calibration:Lifetime method
Merged-beams rate coefficient signal
http://www.mpi-hd.mpg.de/ion-storage
Molecular recombination measurements: Analysis
Binned cross section
O. Novotný, Astrophys. J. 777, 54 (2013)HCl+ + e → H + Cl + εkin
http://www.mpi-hd.mpg.de/ion-storage
Molecular recombination measurements: Analysis
Maxwellian distribution
Plasma rate coefficient
O. Novotný, Astrophys. J. 777, 54 (2013)
~8% uncertainty
300 K internalion temperature !
HCl+ + e → H + Cl + εkin
Binned cross section
http://www.mpi-hd.mpg.de/ion-storage
Molecular recombination measurements: AnalysisO. Novotný, Astrophys. J. 777, 54 (2013)
Fit model for temperature curveof rate coefficient
HCl+ + e → H + Cl + εkin
Maxwellian distribution
Plasma rate coefficient
~8% uncertainty
300 K internalion temperature !
Binned cross section
http://www.mpi-hd.mpg.de/ion-storage
Internal rotational excitation
N = 12
3456
N = 1
2
34
56
Storage time (s)
Storage time (s)
Fra
ctio
n
Fra
ctio
n
Tenv
= 300 K
Tenv
= 10 K
Tsource
= 8000 K
Radiative relaxation only
(electron collisional effectsnot included)
Rotational populations in Π3/2
ground state of HCl+ ionsstored in vacuum
Measurementtime in TSR
http://www.mpi-hd.mpg.de/ion-storage
±300 kV
2 K to 10 Kinner beam vacuum
Cryostat
Positive/negativeion sources
CSR laboratory
5 m
Neutral fragmentdetectors
MPI für Kernphysik, Heidelberg
Ion platform
2 K refrigerator
buffer gaspre-traps
mass filterelectrospray
Location for:
±60 kV
Merged neutral atom beam
Secondion source
H. KreckelASTROLAB
project
Photocathodeelectronbeam
http://www.mpi-hd.mpg.de/ion-storage
CSR: Beam lifetime measurement by photodetachment
Ag2−
EA: 1.02 eV
60 keV Ag2
− + hν (1.9 eV) → Ag2 + e− (A = 216)
τ (20% laser) = 2074(21) sτ (40% laser) = 1676(18) s
τ (no laser) = 2717(81) s
~ 3 h
C. MeyerS. George
O. NovotnýC. Krantz
(MPIK)
Ag2
−
Ag2HeNe laser
chopped( 20% 40% )
~45 min1/e
R. von Hahn et al.,Rev. Sci. Instrum.87, 063115 (2016)
CH+ resonant photodissociationA. O'Connor et al., Phys. Rev. Lett. 116, 113002 (2016)
n < 140 cm−3
PRTE
< 5.8 × 10−15 mbar
Vacuum
http://www.mpi-hd.mpg.de/ion-storage
Installation of the CSR merged electron beam
Storedion
beam
CSR cryostat~1 … 1000 eVelectron beam
Photocathode
http://www.mpi-hd.mpg.de/ion-storage
Acknowledments – TSR
Stefan Schippers
Nigel Badnell
Oldřich Novotný
Claude Krantz
Alfred Müller
Manfred Grieser Daniel Savin
Kaija Spruck
CSR team
Collaborations CSR and experiments
CSR detectors, electron cooler, laser experiments
A. BeckerC. KrantzS. LohmannO. NovotnýS. SaurabhK. Spruck (Univ. Gießen)S. VogelP. WilhelmM. Rimmler
S. GeorgeC. Breitenfeldt (Univ. Greifswald)C. MeyerJ. GöckJ. KartreinP. Mishra
R. von HahnM. GrieserF. FellenbergerS. GeorgeM. LangeR. RepnowP. Herwig
C. KrantzS. VogelK. Spruck (Univ. Gießen)A. BeckerH. Kreckel (Astrolab)F. Grussie (Astrolab)A. O'Connor (Astrolab)
K. Blaum
WIS Rehovot (O. Heber, D. Zajfman)Univ. Greifswald (L. Schweikhard)Bar-Ilan Univ. (Y. Toker)Univ. Gießen (S. Schippers)Columbia Univ. (D. W. Savin)Univ. Louvain-la-Neuve (X. Urbain)Univ. Heidelberg, KIP (A. Fleischmann, C. Enss)Univ. Kaiserslautern (G. Niedner-Schatteburg)
and the MPIK workshops and labs
Acknowledgments – CSR
FundingMPGWIS
DFG Priority Program“Physics of the Interstellar Medium”
NASA and NSF (Columbia Univ.)
S. Schippers (Univ. Gießen)D. Schwalm (MPIK/WIS Rehovot)
Astrolab@CSRH. KreckelA. O'ConnorF. GrussieE. GuerinS. Kumar
ERC
S. Allgeier, C. Enss, A. Fleischmann, L. Gamer, D. Hengstler, S. Kempf, A. Pabiger, C. Pies
Microcalorimeter collaborators from Kirchhoff Inst. of Physics, Univ. Heidelberg:
MPIKC. D. SchröterR. MoshammerT. Pfeifer