Auger Electron Spectroscopy

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Auger Electron Spectroscopy of Double and Triple
Capture in Flourine on Argon Collisions
Arifa Habib
J. R. Macdonald Laboratory
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The Star of this talk, the Tandem Van de
Graaf accelerator
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The Corona point housing
The Charging belt
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The Scenario....

• The 2l2l2l triply excited states of F9 had
  recently been observed in fast energy collisions
  using the method of triple ion capture to a bare
  ion using the paracentric HDA Zamkov. et all,
  Phys. Rev. A, 67, (050703), 2003
• Since these states are not completely described
  within the IPM, C.D. Lin et all were working on
  new ways to describe these states from the
  correlated motion of the electrons within the
  state. Phys.Rev. A, 67, 022511

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The plan.......
Take advantage of the better resolution of the
tandem parallel plate spectrometer designed by H.
Aliabadi to find the absolute SDCS and compare
the ratios of the following processes

• triple electron capture double capture in F9
  at different beam energies
• double capture of F8 to triple capture in F9
• Excitation capture in F8 to double capture in
  F9.

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The tools....
The electronics set-up
The spectrometer
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The spectrometer, gas cell and channeltron
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Spectrometer resolution found using an electron
gun H. Aliabadi, doctoral thesis, (2004)
The reason for using this spectrometer.....
?E Epass R E E
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And.....results.........(reality kicks in!)
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What the previous graph means.....
Peak designations 1 525.4 eV, (1s2s2)2S 2
529.4 eV, (1s2s2p)4P 3 539.9 eV, (1s2s2p)2P_ 4
544.9 eV, (1s2p2)4P 5 551.0 eV, (1s2p2)2D 6
561.1 eV, (1s2p2)2S
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Yes, but whats it all about ?
Zero degree projectile Auger electron full
spectrum
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On to cross section calculation....
DDCSi


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What was discovered...
at 16 MeV
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and...the triply excited states!
Triple Capture, 2l2l'2l'' Triple Capture, 2l2l'2l'' Triple Capture, 2l2l'2l'' Triple Capture, 2l2l'2l'' Triple Capture, 2l2l'2l''
Peak LINE LINE ENERGY HSCC calc.
  Initial Final (eV)  
8 (2s2p2) 4P (1s2p)3P 599.50.6 599.29
1(a) (2s2p2) 2D (1s2s) 1S 6090.6 609.35
1(b) (2s2p2) 2D (1s2p) 3P 6090.6 609.74
2 (2s2p2) 2P (1s2p) 1P 610.50.3 611.73
3 (2p3) 2D (1s2p) 1P 612.70.4 613.60
4 (a) (2s2p2) 2S (1s2s) 1S 616.30.5 617.08
4 (b) (2s2p2) 2S (1s2p) 3P 616.30.5 617.47
5 (a) (2s2p2) 2P (1s2p) 3P 618.30.3 618.11
5 (b) (2s2p2) 2D (1s2s) 3S 618.30.3 618.39
5 (c) (2p3) 2D (1s2p) 3P 618.30.3 619.04
6 (2s2p2) 2S (1s2p) 3S 625.50.3 625.73
7 (2p3) 2P (1s2p) 3P 627.20.3 627.12
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and at 19 MeV..
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Ratio of double to triple capture...
Ratio of double to triple capture Ratio of double to triple capture
16MeV 19 MeV
2l2l' to 1s2l2l' 1.410.1 1.390.1
2l2l' to 2l2l'2l'' 6.581.0 4.690.6
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and ...
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The only energy dependence of cross sections
calculation so far......
Absolute SDCS measurements of triple
electron capture to the C3 KLL states,
populated in collisions of bare
carbon ions with Ar targets.
Phys. Rev A, 66, 042714 (2002)
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and more ...
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and more ratios .....
Double capture F8 to Triple capture F9 2.72
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and more ratios .....

• F9 Double capture to F8 excitation capture
  5.99
• Results of individual lines not plotted
  yet

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So for the future....

• During last summer and this semester the
  paracentric spectrometer has been improved
• It is hoped that the improvements will allow us
  to operate with higher decel factors and thus
  obtain higher energy resolustion.
• Its therefore to repeat all of this on the
  paracentric HDA!
• so
  that
• we can further investigate the beam energy
  dependence of triple to
  double capture.
• Thanks for listening !

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Just in case someone asks....