Solid angle correction factors for hemispherical and two-stage parallel plate analysers in the detection of long lived projectile Auger states

Manolis Benis

Department of Physics, University of Ioannina

9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Ion-atom Collisions

Atomic Energy levels K capture K ionization continuum K-M excitation E a - Auger energy e-e interaction M L M-K radiative transition E x KLM Auger transition K Z p e Ion-atom collision e v t V p Atomic Structure : q, Z p , Z t , E x , E a … Collision Dynamics: b, V p Cross section:  (

V p

,

q

,

Z p

,

b

, , v t v

t

,

Z t

… ,

E a

,

E

x ,...)

HCI

: Few -electrons - simpler environment Projectile Ion Charge q+ Z t Target Atom b for testing theories Projectile spectroscopy: Control # of electrons on ion by selecting its charge Special interest: Two-electron processes, e correlations and deviations from the IPM 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Ion-atom Collisions: Electron Spectroscopy

d



d

 

N I



n



l



N e

 0 

T

 

d



d



d



d



PROMPT



N PROMPT N e



n



l



T

  1  0

META



N META



N n e



l



T

  1 

eff d



d



META



d



d



PROMPT N PROMPT N META

 0 

eff

9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

The effective solid angle correction factor

Hemispherical Deflector Analyser

12 MeV C

4+

(1s2s2p

4

P

J

)

Doukas et al, Rev. Sci. Instr. 86 043111 (2015) 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

The effective solid angle correction factor

Hemispherical Deflector Analyser SIMION Monte Carlo type Calculations

2.0

5 F = 4 s 0 = 289 mm 4 3 SIMION Analytical (  max = 2.2

o ) 1.5

1.0

 max =  kinem = 40.3

o  max = 2.0

o  max = 1.8

o  max = 1.5

o  max = 1.0

o SIMION F = 4 4 P 2 0.5

1 0 10 1 10 2 V P  (mm) 10 3 10 4 0.0

225 226 227 228 229 230 231 Auger Electron Energy (eV) Benis et al, submitted to NIMB

The lens filters out emitting angles higher than 2

o 232 233 The lens also filters out electrons generated within it … 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

SIMION simulations

Hemispherical Deflector Analyser

Doukas et al, Rev. Sci. Instr. 86 043111 (2015) 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

The effective solid angle correction factor

Tandem Parallel Plate Analyser Work In Progress …!

L 2 x w l d S L 1

5.0x10

-4 4.0x10

-4 3.0x10

-4 2.0x10

-4 Geometrical SIMION 1.0x10

-4 0.0

100 80 60 x (mm) 40 20 0 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Mixed state (1s

2 1

S, 1s2s

3

S ) beams

d d

  

N I

spectrum. 

n



l



N e

 0 

T

  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!

Practically ground state (1s < 3% metastable 2 ) Ion Beam obtained by gas stripping at lower energies Use both measurements to obtain the fractions Benis et al, Phys. Rev. A 65, 064701 (2002) 4 MeV B 3+ + H 2 2 0 6 4 14 12 10 8 f 3 S = 25% 14 12 10 8 6 4 f 3 S < 3% 2 0 150 152 154 156 158 160 162 164 166 168 170 Electron Energy (eV) 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Application: Populating the 1s2l2l' states

Probability ( 1

s

2

s

3

S

) 2

p

4

P

4 6 Spin recoupling ( 1

s

( 2

s

2

p

) 3

P

) 4

P

6 4 1

s

2

s

3

S

+ 2p ( 1

s

( 2

s

2

p

) 3

P

) 2

P

 ( 1

s

2

s

3

S

) 2

p

2

P

2 6 Final breakdown

4 P : 2 P : 2 P

8 12  1 12  3 12

+

R

 4

P

2

P

  2

P

  2 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015 ( 1

s

( 2

s

2

p

) 1

P

) 2

P



R

 2

P

 2

P

  3 4 3 4 1

Literature Overview

7 6 5 4 3 Data: Lee (1991) Tanis (2004) 2 1

F 7+ (1s 2 /1s2s 3 S) + He

0 0.2

0.4

0.6

0.8

1.0

1.2

1.4

Projectile Energy (MeV/u) 1.6

1.8

2.0

Spin statistics Strohschein et al, Phys. Rev. A 77, 022706 (2008) 5 4 7 6 3 2 1.875

1 0

F 7+ (1s 2 /1s2s 3 S) + H 2

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Projectile Energy (MeV/u) 1.6

1.8

2.0

Zouros et al, Phys. Rev. A 77, 050701(R) (2008) 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Literature Overview

Pauli Exchange Interaction

nl

Radiative Cascade feeding

Tanis et al, Phys. Rev. Lett. 92, 133201(2004) Zouros et al, Phys. Rev. A 77, 050701(R) (2008) 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Revisit of older data

12 MeV C 4+ (1s2s 3 s) + He

Rohrbein et al, Phys. Rev. A 81, 042701 (2010) 4 MeV B 3+ + H 2 2 0 6 4 14 12 10 8 f 3 S = 25% 14 12 10 4 2 8 6 f 3 S < 3% 0 150 152 154 156 158 160 162 164 166 168 170 Electron Energy (eV) Benis et al, Phys. Rev. A 65, 064701 (2002) 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Current and future prospects

  Investigation of the systematics of the 4 P/ 2 P ratio in an isoelectronic sequence study using He-like ions from Li + C 4+ , N 5+ , O 6+ , F 7+ in the 0.1-2 MeV/u , B 3+ , Use different targets such as H 2 , He, Ne, Ar • • 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 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Ongoing Research

New targets 6 4

12 MeV C 4+

2 0 4 2 0 220 2 0 4 2 0 4 2 Norm.yields

Norm.fit 225 S 4 P 2 2 P+ 2 D W=1521eV,F=4, VL4 =-684.45V, VL5=1399.32V

230 235 240 Auger electron Energy (eV) 245 Ne He H 2 Ar 250 6 5 4 3 2 3 2 1 0 220 5 4 1 0 6 2 225 S 2 S 4 P

12 MeV C 4+

W=1521eV, F=4 Ne (20 mTorr) Fit 4 P Higher Energy – 18 MeV 2 P + 2 P 2 D Ar (5 mTorr) Fit 3 2 1 0 3 2 S 4 P

18 MeV C 4+

W=1966eV, F=4 Ne (20 mTorr) Fit 4 P 2 P 2 P+ 2 D Ar (5 mTorr) Fit 2 2 P 2 P + 2 D 230 235 1 2 S 240 245 250 0 220 225 Auger Electron Energy (eV) 230 2 P 2 P + 2 D 235 240 245 250 New calculations are needed to evaluate capture collision systems and cascade contributions for all measured 9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015

Thank you for your attendance

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 377289.

9th International Physics Conference of the Balkan Physical Union, Istanbul, 24-27 August 2015