Manolis Benis Auger electron yields of metastable Li-like projectile states repopulated by radiative cascades and Auger depletion Department of Physics, University of Ioannina SPARC workshop, Fodele, September 22-27, 2015

Ion-atom Collisions continuum K L M K capture K-M excitation E a - Auger energy KLM Auger transition e-e interaction Atomic Energy levels K ionization Atomic Structure Atomic Structure: q, Z p, Z t, E x, E a … Collision Dynamics Collision Dynamics: b, V p, v t … Cross section Cross section: Highly Charged Ions Highly Charged Ions: Few-electrons - simpler environment for testing theories M-K radiative transition ExEx VpVp ZpZp ZtZt b e-e- e-e- Ion-atom collision vtvt Projectile Ion Charge q+ Target Atom

Highly Charged Ions SPARC workshop, Fodele, September 22-27, 2015  Basic understanding of atomic collision processes  QED corrections  Astrophysical plasmas  Cometary X-ray emission  Fusion research  Radiation damage  HCI nano-structuring of surfaces  Guiding of HCI in insulator nano-capillaries  Accelerator physics  Instrumentation R & D

Projectile Spectroscopy SPARC workshop, Fodele, September 22-27, 2015  Control of the number of electrons on the projectile  Fewer electrons  Less complicated system  Metastable ionic beams  Easy to study iso-electronic sequences  C 3+ (1s 2 2s), B 2+ (1s 2 2s), Be + (1s 2 2s), …  Low-Z projectiles  High Auger electron yields  Kinematic advantages  Zero-degree Auger Projectile Spectroscopy (ZAPS)

T+NTE SPARC workshop, Fodele, September 22-27, 2015 Populating the 1s2l2l' states NTE V V RTE TargetProjectile V T (or C)

SPARC workshop, Fodele, September 22-27, 2015 Spin statistics for 2p capture to 1s2s 3 S + 2p 4 P : 2 P - : 2 P + Finalbreakdown Probability Spin recoupling

SPARC workshop, Fodele, September 22-27, 2015 Literature Overview Spin statistics Strohschein et al, PRA (2008) Zouros et al, PRA (2008)

SPARC workshop, Fodele, September 22-27, 2015 Pauli exchange interaction (?) A target electron with spin aligned to the spin of the 1s projectile: b) cannot be captured into the 1s (or 2s) due to Pauli exclusion. Tanis et al, PRL (2004) The Pauli Exchange Interaction is reminiscent of the Transfer-Excitation mechanism, but with two identical electrons doing the Transfer and the Excitation! - Rather puzzling and difficult to calculate (not possible to date!) - Rather puzzling and difficult to calculate (not possible to date!) New idea: So instead it interacts with the 1s (or 2s) via a Pauli Exchange Interaction with one e- transferred to the 2p forming additional 4P states a) can be captured into the 2p directly to form the 1s2s2p 4 P

SPARC workshop, Fodele, September 22-27, 2015 Radiative Cascade feeding (?) Significant capture to higher n=3-7 indicated by CDW calculations nl Zouros et al, PRA (2008)

SPARC workshop, Fodele, September 22-27, 2015 Radiative Cascade feeding (?)

4MeV B 3+ [1s 2 1 S, 1s2s 3 S] + H 2 SPARC workshop, Fodele, September 22-27, 2015 RTE Capture Mixed state (1s 2 1 S, 1s2s 3 S ) beams No lifetime/solid angle corrections Benis et al, PRA (2002)

SPARC workshop, Fodele, September 22-27, 2015 Mixed state (1s 2 1 S, 1s2s 3 S ) beams Practically ground state (1s 2 ) spectrum. < 3% metastable Ion Beam obtained by gas stripping at lower energies Mixed state (1s 2, 1s2s 3 S) spectrum 25% metastable Ion Beam obtained by foil stripping “Subtract” spectra to obtain pure metastable beam 1s2s 3 S spectrum!

Mixed state (1s 2 1 S, 1s2s 3 S ) beams Strohschein et al, PRA (2008) SPARC workshop, Fodele, September 22-27, 2015

The effective solid correction factor Hemispherical Deflector Analyser 12MeV C 3+ (1s2s2p 4 P J ) Doukas et al, Rev. Sci. Instr (2015) SPARC workshop, Fodele, September 22-27, 2015

Benis et al, NIMB (2015) In press The effective solid angle correction factor The lens filters out emitting angles higher than 2 o The lens also filters out electrons generated within it … Hemispherical Deflector Analyser SIMION Monte Carlo type Calculations SPARC workshop, Fodele, September 22-27, 2015

SIMION simulations Doukas et al, Rev. Sci. Instr (2015) SPARC workshop, Fodele, September 22-27, 2015

Revisit of older data Benis et al, PRA (2004) SPARC workshop, Fodele, September 22-27, 2015

Tandem Parallel Plate Analyser d L1L1 L2L2 S x w l A spectrometer with well defined solid angle ? The effective solid angle correction factor

SPARC workshop, Fodele, September 22-27, 2015 Cascade Feeding and depletion of a state Order depopulationpopulation Curtis, Am. J. Phys (1968)

SPARC workshop, Fodele, September 22-27, 2015 More SIMION simulations … Include cascade feeding theoretical calculations in the Monte Carlo SIMION simulations Direct comparison to the experiment! the experiment! (No correction factors …) Direct comparison to the experiment! the experiment! (No correction factors …) Calculations by T. Kirchner Testing ground

SPARC workshop, Fodele, September 22-27, 2015 Spin statistics for 2p capture to 1s2s 3 S

SPARC workshop, Fodele, September 22-27, 2015 Mid-Future Prospects SPARC collaboration: Extend our studies to high(er) Z elements  Locate candidate metastable electronic configurations LS  jj coupling nomenclature, theorists help  Develop a TDR Current electron spectrometer in a new setup (UHV chamber, gas jet, etc.)  Get approved and … Ask for funding …

Current and near-future prospects In progress: Installation of terminal gas stripper to produce ground state beams Installation of post strippers (foil and gas) to produce He-like ions at lower energies Investigation of the systematics of the 4 P/ 2 P ratio in an isoelectronic sequence study using He-like ions from Li +, B 3+, C 4+, N 5+, O 6+, F 7+ in the MeV/u Investigation of the systematics of the 4 P/ 2 P ratio in an isoelectronic sequence study using He-like ions from Li +, B 3+, C 4+, N 5+, O 6+, F 7+ in the MeV/u Use different targets such as H 2, He, Ne, Ar Use different targets such as H 2, He, Ne, Ar SPARC workshop, Fodele, September 22-27, 2015

Ongoing Research New calculations are needed to evaluate capture and cascade contributions for all measured collision systems New targets Higher Energy – 18 MeV SPARC workshop, Fodele, September 22-27, 2015

The People 5MV Tandem NCSRT Demokritos, Greece Dr. S. Harissopulos (Director), A. Lagogiannis, M. Axiotis, M. Andrianis University of Crete, Greece Prof. T.J.M. Zouros A. Dimitriou (Post doc), I. Madesis (PhD), A. Laoutaris (MSc), Ch. Nounis (MSc) University of Ioannina, Greece Prof. M. Benis S. Doukas (MSc) ATOMKI, Debrecen, Hungary Prof. B. Sulik University of Isparta, Turkey Prof. O. Sise York University, Toronto, Canada Prof. T. Kirchner Universidade Nova de Lisboa, Portugal Prof. J.P. Santos, Prof. F. Parente, Prof. M.C. Martins Sorbonne Universités, Paris, France Prof. P. Indelicato Co-financed by the European Union and Greek national funds through OP: Education and Lifelong Learning, Research Program: THALES Grant # MIS Funded by the APAPES Project: SPARC workshop, Fodele, September 22-27, 2015

Thank you for your attendance SPARC workshop, Fodele, September 22-27, 2015 Acknowledgement: This research has been co-financed by the European Union (European Social Fund ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) Research Funding Program: THALES. Investing in knowledge society through the European Social Fund, grant number MIS