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Spectroscopic Research Projects on Heavy Elements at NIST

Spectroscopic Research Projects on Heavy Elements at NIST

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Spectroscopic Research Projects on Heavy Elements at NIST

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  1. Spectroscopic Research Projects on Heavy Elements at NIST Wolfgang L. Wiese National Institute of Standards and Technology (NIST), USA

  2. Participants Experimental Research: J. Reader, G. Nave, J. Gillaspy, M. Bridges,* W. Wiese* Theoretical Approaches: Ch. Froese-Fischer,* Y. Ralchenko,* Y.-K. Kim , P. Stone* Data Assessment and J. Reader, E. Saloman,* Compilations: J. Fuhr,* D. Kelleher,* L. Podobedova,* A. Kramida,* W. Wiese* Database Development: Y. Ralchenko,* A. Kramida* R. Ibacache *indicates Contractors or Guest Researchers

  3. Three On-going Spectroscopic Research Projects on Heavy Elements at NIST 1. An updated and expanded critical compilation of spectroscopic reference data for Fe I and Fe II, focusing on better transition probabilities. 2. Calculations of ionization and excitation cross-sections of neutral and singly ionized Mo and W with the Binary-Encounter-Bethe (BEB) model. 3. Experimental observations of the spectra of highly charged tungsten ions, in the range from W+35 to W+63, with an Electron Beam Ion Trap (EBIT) and their analysis. .

  4. Fe I O’Brian 180 lifetimes and branching fractions Blackwell absorption (based on one lifetime)

  5. Fe I Kock several lifetimes and branching fractions

  6. Fe II

  7. Fe II Raassen = semi-empirical calculation

  8. Fe I 2006 1988

  9. Fe II 2006 1988

  10. Electron-Impact Cross Section Database(http://physics.nist.gov/ionxsec)M. A. Ali, K. K. Irikura, Y.-K. Kim, P. M. Stone Already in the database: 1. Total ionization cross sections of neutral atoms and molecules, singly charged molecular ions (about 100) 2. Differential ionization cross sections of H, He, H2 3. Excitation cross sections of light atoms New results to be added by summer, 2007: 4. Total ionization cross sections (direct + excitation-autoionization) of Mo, Mo+, W, W+ (joint work with KAERI, see graphs)—BEB model plus BE/E scaling of Born cross sections [Mo/Mo+ in Kwon, Rhee & Kim, Int. J. Mass Spectrometry, 245, 26 (2005)] 5. Excitation cross sections of H2 (see graphs)—BE scaling of Born cross sections 6. Ionization cross sections of Si, Ge, Sn, Pb, Cl, Br, I, Cl2, Br2, I2

  11. A Major Spectroscopic Research Project on Heavy Elements at NIST • Experimental observations of the spectra of highly charged tungsten ions, in the range from W+35 to W+63, with an Electron Beam Ion Trap (EBIT) and their theoretical analysis.

  12. SPECTRUM OF W IN ORMAK INTERPRETATION AS W XXX - W XXXV ISLER, NEIDIGH, AND COWAN (1977)

  13. 1S0-1P1 1/2-3/2 1/2-1/2 Cu and Zn sequences to W READER & LUTHER (1980)

  14. The NIST Electron Beam Ion Trap (EBIT) The EBIT not only creates a highly charged ions, but can hold their center of mass at rest. This overcomes the primary limitation of large HCI facilities for precision spectroscopy. EBIT size ~ 1 m To first order, the relative Doppler shift is Dl/l =v/c

  15. 107 K plasma EBIT Internal View EBIT on a table top Ion production, trapping, and excitation http://physics.nist.gov/ebit

  16. A simplified EBIT: Intense Electron Beam (4,000 A/cm2) Strong magnetic field (3 tesla) Highly Charged Ions (up to Bi72+at NIST). 2 cm Ultrahigh vacuum (~10-10 torr) Creates (by electron impact ionization) Traps (by electric and magnetic fields) Excites (electron impact) Ion cloud width ~ 150 mm

  17. 0.1-33 keV e-beam energy NIST EBIT Q up to 72+ produced Ne-like U82+ threshold: 10 keV (10 remaining electrons) He-like U90+ threshold: 33 keV (2 remaining electrons) J.D. Gillaspy, Phys. Scr. T71, 99 (1997).

  18. Quantum Microcalorimeter • operates at 65 mK • absorber: a foil of • superconducting tin • thermistor: neutron • transmutation-doped • (NTD)germanium

  19. “Crystal-quality” resolution, wide bandwidth and 100% efficiency. Ar L-shell K-shell

  20. EUV SPECTROMETER AT NIST EBIT BLAGOJEVIC, LE BIGOT, ET AL. (2005)

  21. IONIZATION ENERGIES FOR W IN ALL STAGES KRAMIDA & READER (2006)

  22. = THIS WORK

  23. IONIZATION ENERGIES OF W IONS

  24. W I & II (260 pages) W III - LXXIV (~250 pages) COMPILATIONS of W SPECTRA AND ENERGY LEVELS KRAMIDA & SHIRAI (2006 & 2007)

  25. COWAN (1977) vs. OBSERVED IE’s SEMI-EMPIRICAL - KRAMIDA & READER (2006)

  26. Br Br O O Ge Ge Ga Ge Ga Zn Zn Zn Cu Cu Cu Cu

  27. COUNTS EXPERIMENT THEORY CR MODELING OF PLASMA OF W IN NIST EBIT - RALCHENKO ET AL. (2007)

  28. Cu * = 2 or 3 rd order + = O or N Cu Ni UTA Cu Ni Cu Ni UTA Co Ni Zn SPECTRUM OF W IN NIST EBIT AT 4228 eV RALCHENKO ET AL. (2007)

  29. 4f 4p 4s 5f 6f X-RAY SPECTRUM OF W WITH MICROCALORIMETER ON NIST EBIT 3d10-3d9nl RALCHENKO ET AL. (2006)

  30. 2 1 7.610 Å L 3d94s 2 3 E2 M 7.930 Å E2 3d10 0 E2 LINES OF W IN NIST EBIT - RALCHENKO ET AL. (2006)

  31. 4f 4p 4s 5f 6f X-RAY SPECTRUM OF W WITH MICROCALORIMETER ON NIST EBIT 3d10-3d9nl RALCHENKO ET AL. (2006)

  32. 2 1 7.610 Å L 3d94s 2 3 E2 M 0.009 Å 7.930 Å M3 E2 3d10 0 E2 AND M3 LINES OF W IN NIST EBIT RALCHENKO ET AL. (2006)

  33. CALCULATED E2:M3 RATIOS RALCHENKO J. Phys. B: At. Mol. Opt. Phys. 40 (2007) F175