highly charged ions 5.5MV Demokritos Atomic Physics with Accelerators: Projectile Electron Spectroscopy of highly charged ions at the 5.5MV Demokritos Tandem accelerator Theo J.M. Zouros University of Crete Keynote presentation June 3, 2016 HNPS Demokritos-Athens SIMION simulation Cascade feeding APAPES

03/06/2016 HNPS Demokritos-Athens 2 Basic ion-atom collision processes continuum K L M L capture K-M excitation ε a - Auger energy KLM Auger transition e-e interaction Ion Energy levels K ionization Atomic Structure: q, Z p, Z t, ε x, ε a … Collision Dynamics: b, V p, v t … Cross section: σ(V p,q,Z p,b,v t,Z t,ε γ,ε a …) Few HCI: Few-electrons much simpler environment for testing theories Isoelectronic investigations Special interest: Two-electron processes and deviations from the independent particle model M-K radiative transition εγεγ VpVp ZpZp ZtZt b e-e- e-e- Ion-atom collision vtvt Projectile Ion Charge q+ Target Atom

03/06/2016 HNPS Demokritos-Athens 3 Force is Coulomb: Force is Coulomb: Potential usually known - can write down a Hamiltonian Potential usually known - can write down a Hamiltonian Objective: Calculate emission or interaction cross sections Objective: Calculate emission or interaction cross sections Difficulties: many particles, long range force, correlation effects Difficulties: many particles, long range force, correlation effects Model calculations Model calculations Experimental techniques – state selective measurements Experimental techniques – state selective measurements Test approximations Test approximations Mature field – more than 50 years old ! Ion-atom/electron interactions: Investigation of the Coulomb force With new technologies in Highly Charged Ion (HCI) sources and heavy-ion storage rings – gradual shifting to: Low energy HCI collisions High-Z HCI collisions (FAIR/SPARC)

03/06/2016 HNPS Demokritos-Athens 4 Interest in Highly Charged Ions (HCI) Basic understanding of atomic collision processes (simpler systems, isoelectronic studies) High-Z HCI used to test QED corrections (spectroscopy) Astrophysical plasmas (Solar Corona etc.) Fusion research (ionization, recombination - plasma edge modeling, plasma-wall interactions, diagnostics - JET, ITER) Cometary X-ray emission (Charge-exchange of solar wind HCIs with cometary vapors) Radiation damage, Therapy of deep-seated localized tumors (energy loss, HCI bombardment of sensitive areas (brain, eye), narrow Bragg peak) HCI nano-structuring of surfaces (nano-hillock formation, potential sputtering) Guiding of HCI in insulator nano-capillaries Accelerator physics (source development, lifetime of particle beams in storage rings, radioactive beams) Instrumentation R & D Training of young researchers in the use of accelerators

Radiative transitions – Characteristic x-rays 03/06/2016 HNPS Demokritos-Athens 5 e- photon 1 2 K (1s) L (2s) L (2p) continuum εγεγ Nobel Prize in Physics in 1917 for his work in X-ray spectroscopy Charles Glover Barkla (1877 –1944) Selection rules ΓRΓR

Radiationless transitions: KLL - Auger transitions 03/06/2016 HNPS Demokritos-Athens 6 continuum e- εaεa Auger energy e- 1 2 K (1s) L (2s) L (2p) P. Auger (1923): Sur les rayons β secondaires produits dans un gaz par des rayons X, Compt. Rend. 177, Sur les rayons β secondaires produits dans un gaz par des rayons X Pierre Auger (1899 –1993) Cosmic Rays Selection rules ΓAΓA ε a = B K -B L 1 -B L 2 Mendoza, Argentina

ΓRΓR ΓAΓA Transition Rates photon Radiationless transitions: K-Auger transitions 03/06/2016 HNPS Demokritos-Athens 7 εaεa continuum Auger energy For low Z Γ R << Γ A e- 1 2 K (1s) L (2s) L (2p) ε a = B K -B L 1 -B L 2 K-Auger e- spectroscopy much more efficient! ΓRΓR ΓAΓA

Projectile Auger electron kinematics: 03/06/2016 HNPS Demokritos-Athens 8 Velocity Addition: V lab = V p + v’ Vp > v’Vp > v’ Vp < v’Vp < v’ At θ=0 ο (θ’=0 o or 180 ο ) VpVp

Projectile Auger electron kinematics: 03/06/2016 HNPS Demokritos-Athens 9 Kinematic Broadening – smallest at θ=0 0 observation Kinematic Broadening Δε~Δθ 2 at θ=0 0 Experimental Resolution: Δε 0 /ε 0 ~ 0.1%

03/06/2016 HNPS Demokritos-Athens 10 Populating the 1s2l2l' states from the 1s 2 T+NTE TE Li-like Ion B 2+ He-like Ion B 3+

03/06/2016 HNPS Demokritos-Athens 11 Populating the 1s2l2l' states from the 1s 2 T+NTE TE He-like Ion B 3+ Li-like Ion B 2+ Target Projectile TE VpVp Transfer – Excitation from 1s 2 1s-2p Excitation 2s Transfer 1s-2p Excitation + 2s Transfer 2p 2s 1s

03/06/2016 HNPS Demokritos-Athens 12 T+NTE TE Li-like Ion B 2+ Populating the 1s2l2l' states from the 1s2s 3 S He-like Ion B 3+ TargetProjectile 2p Transfer T VpVp Transfer (e- capture) to 1s2s 3 S

He-like Ion B 3+ 03/06/2016 HNPS Demokritos-Athens 13 TE Li-like Ion B 2+ Populating the 1s2l2l' states from the 1s 2 and the 1s2s 3 S Both 1s 2 and 1s2s 3 S States contribute to the Populations of the 1s2l2l’ lines Goal: to separate the capture from the TE contributions and understand mechanisms involvedTE

Plan for atomic physics beam line L45 at Demokritos 5.5MV Tandem accelerator 03/06/2016 HNPS Demokritos-Athens 14 November 2012 Aug 2009 opening call for THALES Apr 2012 signed THALES grant (almost 3 years later!!!) Dec 2012 found and hired first PhD student Sep 2013 found and hired first Post Doc

New beam line L45 and experimental setup at the 5.5 ΜV Δημόκριτος Tandem 03/06/2016 HNPS Demokritos-Athens Doublet: Beam focusing 2 - Magnetic Steerers 3 - Beam Profile Monitor 4 - Dif. Pumped Gas target 5 - Chamber with HDA l/s turbo pumps L45 and Spectroscopy Setup Completed July 2014

Spectrometer chamber and Target Gas Cell 03/06/2016 HNPS Demokritos-Athens 16 μ-metal shielding For high resolution studies μ-metal shielding is important Double differential pumping Keeps the beam line vacuum good

03/06/2016 HNPS Demokritos-Athens 17 New ZAPS setup: Single stage 0 0 HDA with injection lens and 2-D position sensitive detector HCI Target gas n t ~10 12 #/cm 3 Differential Pumping ports Focusing and retardation Chamber pressure ~10 -7 Torr Overall efficiency gain ~ High Transmission ~ 90% Paracentric entry E E+ΔE

Spectrometer High Voltage computer control and detection Electronics 03/06/2016 HNPS Demokritos-Athens 18

2-D position sensitive detection system 03/06/2016 HNPS Demokritos-Athens 19 Looks like a misalignment of the 4 P peak With additional μ-metal shielding The rest of the peaks are now brought Into alignment With the 4 P peak

Demokritos Tandem Laboratory Ion Strippers Installation 5.5 MV Tandem accelerator Post strippers Ion sources q = -1 + q i Terminal strippers Ion Beams L45 ZAPS Beam line

5.5 MV Tandem accelerator Post strippers Ion sources q = -1 + q i Ion Beams L45 ZAPS Beam line Foil post stripper Demokritos Tandem Laboratory Ion Strippers Installation

5.5 MV Tandem accelerator Post strippers Ion sources q = -1 + q i L45 ZAPS Beam line Gas post stripper Ion Beams

5.5 MV Tandem accelerator Ion sources q = -1 + q i Terminal strippers Ion Beams L45 ZAPS Beam line Terminal strippers Demokritos Tandem Laboratory Ion Strippers Installation Ion beam

TARDIS TARDIS: Transmitted chARge DIStribution* 03/06/2016 HNPS Demokritos-Athens 24 *by Eleni Myrto Asimakopoulou TARDIS TARDIS computes the resulting charge state distributions after passage through foil or gas and displays the results in an easy to view graph

C 4+ ion beams produced by stripping 03/06/2016 HNPS Demokritos-Athens 25 Terminal stripping All charge states Foil Gas Terminal + Post stripping Only C 4+

Mixed state (1s 2 1 S, 1s2s 3 S ) beams and gas terminal stripping! 03/06/2016 HNPS Demokritos-Athens 26 Mixed state (1s 2, 1s2s 3 S) spectrum 25% metastable Ion Beam obtained by foil stripping Practically pure ground state (1s 2 ) spectrum. < 3% metastable Ion Beam obtained by gas stripping at lower energies “Subtract” spectra to obtain pure metastable beam 1s2s 3 S spectrum! Benis et al, PRA (2004) Mixed beam Ground State Only!

Mixed state (1s 2 1 S, 1s2s 3 S ) beams 03/06/2016 HNPS Demokritos-Athens 27 Strohschein et al, PRA (2008) Pure 1s2s 3 S Mixed and ground state

03/06/2016 HNPS Demokritos-Athens 28 Ratio of 4 P/ 2 P for capture to C 4+ (1s2s 3 S) Pure 1s2s 3 S Strohschein (2008) Theory

Strohschein (2008) 03/06/2016 HNPS Demokritos-Athens 29 Our MIXED beam results Ratio of 4 P/ 2 P for capture to C 4+ (1s2s 3 S) Need pure ground state beam spectra For background subtraction! 4 P Cascade Feeding calculations Our projected ratio Theory

Summary and outlook 03/06/2016 HNPS Demokritos-Athens 30 ESSENTIAL Gas terminal stripper ESSENTIAL for “background” subtraction to obtain pure 1s2s 3 S contributions Determine ratio of 4 P/ 2 P in dispute Understand cascade feeding that populate the 4 P New experiments APAPES Suggestions for improved Tandem operation: Strong need for night operation sputter Replacement of negative ion sputter source Finish/optimize stripper operation Hope for new €€€€ grants! Mr. Fotakis?!

Dept. of Physics, Univ. of Crete, Heraklion Theo Anastasios Ioannis Angelos Zouros Dimitriou Madesis Laoutaris* (PI & Coordinator) (PostDoc) (PhD student)(MS student) APAPES APAPES participants – Univ. of Crete 03/06/2016 HNPS Demokritos-Athens 31 *SEMFE-NTUA

APAPES APAPES participants – INPP Demokritos 03/06/2016 HNPS Demokritos-Athens 32 Tandem, Institute of Nuclear and Particle Physics NCSRT Demokritos Sotiris Tasos Michalis Miltos Theo Harissopulos Lagoyannis Axiotis Andrianis Mertzimekis Univ. of Athens Myrto Asimakopoulou Tasos Kanellakopoulos

APAPES APAPES participants – last but not least! 03/06/2016 HNPS Demokritos-Athens 33 Manolis Bela Omer Genoveva Jose Paulo Benis Sulik Sise Martinez-Lopez Santos Dept of Physics Univ of Ioannina Greece ATOMKI Debrecen Hungary Univ of Isparta Turkey Dept Fisica Aplicada Un. Complutense De Madrid Spain Dept de Fisica Univ Nova de Lisboa Portugal Ion-atom collisions Electron spectroscopy Electron optics lens experts SIMION simulations Atomic Structure theory Spiros Doukas Masters U. Ioannina SIMION

03/06/2016 HNPS Demokritos-Athens 34 The end More information: apapes Thank you for listening Also 2 posters at HNPS 2016