Exploratory studies towards experimental Exploratory studies towards experimental data for electrondata for electron--impact ionizationimpact ionization

Exploratory studies towards experimental Exploratory studies towards experimental data for electrondata for electron--impact ionizationimpact ionizationdata for electrondata for electron--impact ionization, impact ionization,

electronelectron--ion recombination and ion recombination and h t i i ti f t t ih t i i ti f t t i

data for electrondata for electron--impact ionization, impact ionization, electronelectron--ion recombination and ion recombination and h t i i ti f t t ih t i i ti f t t iphotoionization of tungsten ionsphotoionization of tungsten ionsphotoionization of tungsten ionsphotoionization of tungsten ions

Alfred MüllerAlfred MüllerInstitut für AtomInstitut für Atom-- und Molekülphysikund Molekülphysik

JUSTUS-LIEBIG-ÄI M PA UNIVERSITÄT

GIESSENI M PA

First Technical Meeting on Spectroscopic and Collisional Data for W from 1 eV to 20 keV

IAEA, Vienna, December 13 – 15, 2010

Outline Outline Outline Outline

I. IntroductionI. Introduction

II. Electron-ion recombination

III. Photoionization of ions

IV. Electron impact ionization of ions

V. Outlook and plans

Outline Outline Outline Outline

I. IntroductionI. Introductionatomic data needs – atomic data situation

II. Electron-ion recombination

III Photoionization of ionsIII. Photoionization of ions

IV. Electron impact ionization of ionsIV. Electron impact ionization of ions

V. Outlook and plans

Evolution Evolution ofof tungstentungsten ionion chargecharge statesstates in a in a plasmaplasmaEvolution Evolution ofof tungstentungsten ionion chargecharge statesstates in a in a plasmaplasmaT Pütterich, R Neu, R Dux, A D Whiteford, M G O’Mullane and the ASDEX Upgrade TeamPlasma Phys. Control. Fusion 50 (2008) 085016

rate coefficients for ionization and recombination requiredqIonization: CADW calculations of Ludlow et al. (2005)Recombination: Burgess – Merts (1965 – 1976) with ad hoc modifications

RecombinationRecombination rate rate coefficientscoefficients ofof FeFe15+15+RecombinationRecombination rate rate coefficientscoefficients ofof FeFe15+15+

Murakami et al. 2006 Arnaud Raymond 1992 Brooks et al. 1988 Isler et al. 1982G et al 2004cm

3 /s )

10-10Gu et al. 2004

ent

( c

coef

ficie

10-11 Fe15+

Rat

e c

104 105 106 107

Plasma temperature ( K )

Even for a relatively simple Na like ion care

Plasma temperature ( K )

Even for a relatively simple Na-like ion, care has to be taken when applying existing data

RecombinationRecombination rate rate coefficientscoefficients ofof FeFe15+15+RecombinationRecombination rate rate coefficientscoefficients ofof FeFe15+15+

Murakami et al. 2006 Arnaud Raymond 1992 Brooks et al. 1988 Isler et al. 1982G et al 2004cm

3 /s )

10-10Gu et al. 2004 ADAS (Z. Altun) TSR experiment

ent

( c

coef

ficie

10-11 Fe15+

Rat

e c

104 105 106 107

Plasma temperature ( K )

Even for a relatively simple Na like ion care

Plasma temperature ( K )

Even for a relatively simple Na-like ion, care has to be taken when applying existing data

RecombinationRecombination ofof AuAu25+25+ ( 4f( 4f8 8 ))RecombinationRecombination ofof AuAu25+25+ ( 4f( 4f8 8 ))H

Hoffknecht et al., J. Phys. B 31, 2415 (1998)

Huge crosssections

no individual10

s-1 )

no individual resonancesin spite of highresolution60

80

0-8 c

m3

Flambaum et al. 2002

resolution

new theoreticalaccess to be

40

cien

t ( 1

access to bedeveloped*5

0

20

e co

effic

*See e.g. Flambaum et al.

Electron recombination

0.0 0.1 0.20

eam

s ra

te

with multicharged ions via chaotic many-electron states

Phys Rev A 660

erge

d be

Phys. Rev. A 66, 012713 (2002)0 20 40 60 80M

e

Electron-ion collision energy ( eV )

Data Data situationsituationData Data situationsituation

TheoreticalTheoretical predictionspredictions forfor

ionizationionization andand recombinationrecombination

ofof complexcomplex manymany--electronelectron ionsionspp yy

such such asas WWqq++ ( ( withwith q << Z ) q << Z )

li blli blareare veryvery unreliableunreliable..

Experiments are needed to test and to guideExperiments are needed to test and to guide

theoretical approaches

Available experimental cross section data for

electron-impact ionization of Wq+

Single ionization: q=1,…,10Double ionization: q=1,…,6Triple ionization: q=1,…,4

photoionization of Wq+photoionization of Wq

Single ionization: q=0

electron ion recombination of Wq+electron-ion recombination of Wq

no absolute cross section measurements available

ElectronElectron--impact impact ionizationionization ofof WW1+1+ElectronElectron--impact impact ionizationionization ofof WW1+1+

30

)

20

25

17 c

m2 )

15

20

n (

10-

10

σ for W1+ sec

tion

0

5σ

1,2for W

Stenke et al. 1995 Montague & Harrison 1984C

ross

10 100 1000

0

Electron-ion collision energy ( eV )Electron ion collision energy ( eV )

Outline Outline Outline Outline

I. IntroductionI. Introduction

II. Electron-ion recombinationexperimental status what can be done what has to be done

III Photoionization of ionsIII. Photoionization of ions

IV. Electron impact ionization of ionIV. Electron impact ionization of ion

V. Outlook and plans

Storage ring Storage ring experimentsexperimentsStorage ring Storage ring experimentsexperiments

TSR CRYRINGTSR Heidelberg

CRYRING Stockholm

ESR at GSI Darmstadt

ca. 15 m

The The storagestorage ring TSRring TSRThe The storagestorage ring TSRring TSR

ComparisonComparison ofof advancedadvanced theorytheory withwith experimentsexperimentsComparisonComparison ofof advancedadvanced theorytheory withwith experimentsexperiments

e- + C3+(1s2 2s) → C2+(1s2 2p 4l) → C2+(1s2 2s2) + photons

5 4d 3 D

F

MBPTheory Lindroth CRYRING S. Mannervik et al, PRL 81 (1998) 313 TSR S. Schippers et al., ApJ 555 (2001)

cm-3/s

)

4

2p

, 2p

4f 1 F

(10-1

0 c

3

2p 4

f 3 F,

on ra

te

1

2

d 1 P

4f 3 G

4d 3 P

2p 4

f 3 D

mbi

natio

0

1

2p 4

d

2p 42p 2

Rec

om

0.1 0.2 0.3 0.4 0.5 0.6 0.7

Electron energy (eV)

DielectronicDielectronicrecombinarecombina--DielectronicDielectronicrecombinarecombina-- Fe17+ Fe18+

tiontion of Fe Lof Fe L--shell ions: shell ions: tiontion of Fe Lof Fe L--shell ions: shell ions: a joint a joint USUS--German German a joint a joint USUS--German German project for project for astrophysicsastrophysicsproject for project for astrophysicsastrophysics Fe19+ Fe20+

Columbia-Astrophysics Laboratory

Fe22+Fe21+

Laboratory

Justus-Liebig-Universität Fe22FeGiessen

Max-Planck-Institut für Kernphysik

ConclusionsConclusions so so farfarConclusionsConclusions so so farfar

Merged-beam electron-ion recombination experiments deliver high-accuracy data

Atoms of all elements in any given charge stateare accessible at ion storage ringsare accessible at ion storage rings

State of the art theory provides goodpredictions for light few-electron ions

For complex ions the theory situation is notFor complex ions the theory situation is not satisfying; new theoretical approaches to recombination of many-electron ions have to b d l dbe developed

Only experiments can guide such developmentsOnly experiments can guide such developments

Outline Outline Outline Outline

I. IntroductionI. Introduction

II. Electron-ion recombination

III. Photoionization of ions

IV. Electron impact ionization of ions

V. Outlook and plans

Time‘sTime‘s arrowarrowTime‘sTime‘s arrowarrow

recombination

e-Aq+ [ A(q-1)+ ]**

A(q-1)+

photoionization

e- Aq+[ A(q-1)+ ]**

A(q-1)+ [ A(q-1)+ ]**

A(q-1)+ e-ee

Time Time reversalreversal symmetrysymmetry: : detaileddetailed balancebalanceTime Time reversalreversal symmetrysymmetry: : detaileddetailed balancebalance

Binding energy IAStatistical weight gPI-parent =2

hν + C3+(1s2 2s) C4+(1s2) + e 64 4939 eV

σPI

hν + C3+(1s2 2s) C4+(1s2) + e - 64.4939 eV σRec

Energy Ee = hν - IA

2

2ν

σσ

e

e A

PI parent e A

PI product e e

Rec

PI

E

h E I

g( ) (E I )( ) g E 2m c

−

−= +

+= ⋅

e A PI product e ePI

PhotoionizationPhotoionization ofof ionsions byby synchrotronsynchrotron radiationradiationPhotoionizationPhotoionization ofof ionsions byby synchrotronsynchrotron radiationradiation

ion source

IAMP in collaboration with R. A. Phaneuf et al., University of Nevada RenoUniversity of Nevada, Reno

Time Time reversalreversalofof CC3+3+ photophoto--Time Time reversalreversalofof CC3+3+ photophoto-- 0.10

CRYRING datatime reversed

C3+(1s [2s2p 3P] 2P0)dielectronic

DR data: Mannervik et al., PRA 55, 1819 (1997)

ppionizationionization

ppionizationionization

0.10 time reversed ALS data

dielectronic recombinationof C4+(1s2 1S)

( Mb

)

0.05

σ DR (

CRYRING

Two totally different independently absolute

299.5 300.0 300.50.00

E +64.492 eV

CRYRING

independently absolute measurements.

1000 ALS data

resolution 47 meV Voigt-fit

C3+(1s [2s2p 3P] 2P0)photo excitation

Ee 64.492 eV

ALS500

R-matrix calculation resolution 47 meV

Mb

)pof C3+(1s22s 2S)ALS

0

σ PI (

299.5 300.0 300.5Photon energy ( eV )

A. Müller, S. Schippers, R.A. Phaneuf et al.J. Phys. B 42 (2009) 235602

SummarySummary on on photoionizationphotoionization ofof ionsionsSummarySummary on on photoionizationphotoionization ofof ionsions

complements electron-ion recombination studiescomplements electron ion recombination studies employing detailed balance

hi h l ti iblvery high energy resolution possible

detailed spectroscopy of excited states of ions p pyaccessible

Outline Outline Outline Outline

I. IntroductionI. Introduction

II. Electron-ion recombination

III. Photoionization of ions

IV. Electron impact ionization of ions

V. Outlook and plans

ElectronElectron--ion crossedion crossed--beams setup at IAMPbeams setup at IAMPElectronElectron--ion crossedion crossed--beams setup at IAMPbeams setup at IAMPpppp

Versatile apparatus for studying atomicfor studying atomic collisions

ElectronElectron--ion crossedion crossed--beams setup at IAMPbeams setup at IAMPElectronElectron--ion crossedion crossed--beams setup at IAMPbeams setup at IAMP

ElectronElectron--ionion interactioninteraction regionregionElectronElectron--ionion interactioninteraction regionregion

energy-defining

collector

gy gelectrode

ionscathode

ions

electron current: 450 mA at 1 keV

IonizationIonization ofof complexcomplex ionsions: Xe: Xe2+2+IonizationIonization ofof complexcomplex ionsions: Xe: Xe2+2+

Xe2+(4d105s25p4)

A. Borovik et al., work in progress

150

Xe (4d 5s 5p )

18 c

m2 )

n ( x

10-1

100

sect

ion

50 Giessen absoluteC

ross

0

Giessen energy scan

40 60 80 100 120 140 160 1802000

Electron energy ( eV )

IonizationIonization ofof complexcomplex ionsions: Xe: Xe2+2+IonizationIonization ofof complexcomplex ionsions: Xe: Xe2+2+

Xe2+(4d105s25p4)

A. Borovik et al., work in progress

150

Xe (4d 5s 5p )

18 c

m2 )

n ( x

10-1

100

sect

ion

50 Giessen absoluteC

ross

0

Giessen energy scan Lotz 3-parameter formula

40 60 80 100 120 140 160 1802000

Electron energy ( eV )

IonizationIonization ofof complexcomplex ionsions: Xe: Xe2+2+IonizationIonization ofof complexcomplex ionsions: Xe: Xe2+2+

Xe2+(4d105s25p4)

A. Borovik et al., work in progress

150

Xe (4d 5s 5p )

18 c

m2 )

100n ( x

10-1

100

sect

ion

50 Giessen absoluteGiessen energy scanC

ross

0

gy CADW Loch et al. 2008

40 60 80 100 120 140 160 180200

Electron energy ( eV )

AssumptionsAssumptions, , expectationsexpectations, , generalgeneral wisdomwisdomAssumptionsAssumptions, , expectationsexpectations, , generalgeneral wisdomwisdom

Theory is expected to provide better predictions for more hi hl h d i i i l t ihighly charged ions in an iso-electronic sequence

DW calculations for the direct and the excitation-autoionization contributions should be good for highly g g ycharged ions

IonizationIonization ofof XeXe22+22+IonizationIonization ofof XeXe22+22+

1 0

1.2 DW direct Mandelbaum et al.DW direct + EA

)

0.8

1.0 DW direct EA0-1

8 cm

2 )

0.6

on (

x10

0.4

ss s

ectio

0 0

0.2

Cro

s

700 800 900 1000

0.0

El t i lli i ( V )Electron-ion collision energy ( eV )

P. Mandelbaum, M. Cohen, J.L. Schwob, A. Bar-Shalom, EPJD 33, 213 (2005)

IonizationIonization ofof XeXe22+22+IonizationIonization ofof XeXe22+22+

1 0

1.2 DW direct Mandelbaum et al.DW direct + EA

)

A. Borovik et al., work in progress

0.8

1.0 DW direct EA Giessen absolute Giessen scan

0-18 c

m2 )

0.6

on (

x10

0.4

ss s

ectio

0 0

0.2

Cro

s

700 800 900 1000

0.0

El t i lli i ( V )Electron-ion collision energy ( eV )

Similar discrepancies found for other highly charged ions

ImportanceImportance ofof multiple multiple ionizationionizationImportanceImportance ofof multiple multiple ionizationionizationA B ik t l k i

Xe2+

A. Borovik et al., work in progress

10-16

single ionization)Xe

g

n ( c

m2

sect

ion

double ionization

10-17

Cro

ss double ionization

10-17

0 200 400 600 800 1000

Electron energy ( eV )

ConclusionConclusion on on electronelectron--impactimpact singlesingle ionizationionizationConclusionConclusion on on electronelectron--impactimpact singlesingle ionizationionization

Present state of the art theory can predictcross sections fordirect single ionization of few-electron ionswith high accuracy

Present state of the art theory has difficulties topredict single ionization of complex manypredict single ionization of complex many-electron ions where excitation-autoionizationprocesses prevailp p

There is no theory for multiple ionizationof complex ions

Summary so Summary so farfarSummary so Summary so farfar

Total cross sections for single ionization and for recombinationgas well as for photoionization of few-electron ions are quitewell understood; theoretical data of benchmark quality are (becoming) availablefor few-electron systems

Understanding of collisions and structure of complex ionsis not satisfyingy g

Experiments with complex many-electron systems are required to test and to guide theoretical approachesrequired to test and to guide theoretical approaches

Outline Outline Outline Outline

I. IntroductionI. Introduction

II. Electron-ion recombination

III. Photoionization of ions

IV. Electron impact ionization of ions

V. Outlook and plans

Plans Plans forfor thethe futurefuture: : recombinationrecombination ofof WWqq+ + ionsionsusingusing storagestorage ringsrings

Plans Plans forfor thethe futurefuture: : recombinationrecombination ofof WWqq+ + ionsionsusingusing storagestorage ringsringsgg gg gggg gg gg

TSR ion storage ringTSR ion storage ring in Heidelberg

unique facility withunique facility with optimal features for the purpose

cooler plustarget

excellent energy gyresolution

q up to 50q up to 50 reached

RecombinationRecombination ofof WW20+ 20+ ionsions atat thethe TSR TSR storagestorage ringringRecombinationRecombination ofof WW20+ 20+ ionsions atat thethe TSR TSR storagestorage ringring

S. Schippers et al., in preparation

Plans Plans forfor thethe futurefuture: : photoionizationphotoionization ofof WWqq+ + ionsionsusingusing synchrotronsynchrotron radiationradiation

Plans Plans forfor thethe futurefuture: : photoionizationphotoionization ofof WWqq+ + ionsionsusingusing synchrotronsynchrotron radiationradiationgg yygg yy

photons

Photon-ion spectrometer at PETRA III: PIPE

highest brilliance cwhighest brilliance cw synchrotron radiation up to 3 keV 1012 s-1 per 0 01% b w

2m

10 s per 0.01% b.w.

First First resultsresults on on photoionizationphotoionization ofof WWqq+ + ionsionsobtainedobtained atat thethe ALS in BerkeleyALS in Berkeley

First First resultsresults on on photoionizationphotoionization ofof WWqq+ + ionsionsobtainedobtained atat thethe ALS in BerkeleyALS in Berkeleyyyyy

A. Müller, S. Schippers, A.L.D. Kilcoyne, preliminary results

400

ts) W3+ → W4+

100 meV res10 meV step

400

300

arb.

uni

300

200

ctio

n (a 51.5 52.0 52.5 53.0

100

ross

sec

0

Cr

35 40 45 50 55 60 65

Nominal photon energy (eV)

Plans Plans forfor thethe futurefuture: : electronelectron--impactimpact singlesingle andandmultiple multiple ionizationionization ofof WWqq+ + ionsions

Plans Plans forfor thethe futurefuture: : electronelectron--impactimpact singlesingle andandmultiple multiple ionizationionization ofof WWqq+ + ionsionspppp

New versatile high power, high energy electron gun

high electron currents observed:1A at 3 keV

electron energieselectron energies beyond 6 keV accessible

no other electron-ion experiment in the world canthe world can compete with respect to sensitivity and energy resolution.

ElectricalElectrical currentscurrents ofof isotopeisotope--resolvedresolved WWqq+ + ionsionsfromfrom an allan all--permanentpermanent--magnetmagnet ECR ECR sourcesourceElectricalElectrical currentscurrents ofof isotopeisotope--resolvedresolved WWqq+ + ionsionsfromfrom an allan all--permanentpermanent--magnetmagnet ECR ECR sourcesourcepp ggpp gg

30C+O2+

25W18+ W17+

W16+

20

( nA

)

W20+

W19+ W16+

15+

optimizedfor

15

urre

nt

W21+

W15+

5

10

Ion

cu

W22+

W

0

5W23+

1450 1500 1550 1600 1650 1700 1750 1800 1850

Magnetic field ( G )

HighestHighest chargecharge statesstates ofof WWqq+ + ionsions observedobservedHighestHighest chargecharge statesstates ofof WWqq+ + ionsions observedobserved0 8 Ne3+ N2+

0.8

82 184

W25+

0.005

86

A=1

84 AW29+

=182

0.6

18

186

A)

A=1A

A=1

83

W

A=

0.4 183

W26+

ent (

nA

1300 1305 1310 13150.000

184

186

W28+ W27+

n cu

rre

0.218

2

8383

183

183

184

84

184

86 86

186

W28+

W29+Ion

82

1300 1320 1340 1360 1380 1400 14200.0

1818 118 1 118

1300 1320 1340 1360 1380 1400 1420

Magnetic field ( G )

First First resultsresults on on electronelectron--impactimpact ionizationionization ofof WW17+ 17+

ionsions obtainedobtained in in GiessenGiessenFirst First resultsresults on on electronelectron--impactimpact ionizationionization ofof WW17+ 17+

ionsions obtainedobtained in in GiessenGiessen

17+ 18+

J. Rausch, K. Spruck, A. Becker, K. Huber, S. Schippers, A. Müller, preliminary results

3.00 e + W17+ → W18+ + 2e

cm2 )

2.00( 10-1

8 c

energy scan measurement

sect

ion

1.00energy scan measurement

absolute cross sectionsionization thresholds:

Kramida & ShiraiS fi ld

Cro

ss s

0.00

Scofield Carlson et al.

300 400 500 600 700 800 900 1000

Electron-ion collision energy ( eV )

CooperationCooperationIAMP, Giessen Collaboration of IAMP with:IAMP, GiessenPresent group members

Alfred Müller

Atomic Physics Groups atGSI, DarmstadtMPI-K, Heidelberg

Stefan SchippersKurt HuberSandor Ricz

MPI K, HeidelbergUniversity of StockholmPhysics Department, University of Nevada, Reno

Carsten BrandauAlexander BorovikDietrich Bernhardt

,Columbia University, Astronomy& Astrophysics, New York

Scientific Support Groups atKristof HolsteJan RudolphKatrin MüllerK ij S k

TSR, MPI-K, HeidelbergESR, GSI, DarmstadtALS, LBL, Berkeley

Kaija SpruckJosephina WernerArno BeckerJ H llh d

Atomic Theory Groups atGiessen UniversityUniversity of StockholmU i it f St th l dJonas Hellhund

Joachim RauschUniversity of StrathclydeQueen‘s University, BelfastAuburn UniversityCurtin University PerthCurtin University, Perth

And others occasionally