spectroscopic research projects on heavy elements at nist
Download
Skip this Video
Download Presentation
Spectroscopic Research Projects on Heavy Elements at NIST

Loading in 2 Seconds...

play fullscreen
1 / 40

Spectroscopic Research Projects on Heavy Elements at NIST - PowerPoint PPT Presentation


  • 74 Views
  • Uploaded on

Spectroscopic Research Projects on Heavy Elements at NIST. Wolfgang L. Wiese National Institute of Standards and Technology (NIST), USA. Participants. Experimental Research: J. Reader, G. Nave, J. Gillaspy, M. Bridges,* W. Wiese*

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Spectroscopic Research Projects on Heavy Elements at NIST' - lindley


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
spectroscopic research projects on heavy elements at nist

Spectroscopic Research Projects on Heavy Elements at NIST

Wolfgang L. Wiese

National Institute of Standards and Technology (NIST), USA

participants
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

three on going spectroscopic research projects on heavy elements at nist
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.

.

slide5
Fe I

O’Brian 180 lifetimes and branching fractions

Blackwell absorption (based on one lifetime)

slide6
Fe I

Kock several lifetimes and branching fractions

slide8
Fe II

Raassen = semi-empirical calculation

slide9
Fe I

2006

1988

slide10
Fe II

2006

1988

slide12
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

a major spectroscopic research project on heavy elements at nist
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.
slide16
SPECTRUM OF W IN ORMAK

INTERPRETATION AS W XXX - W XXXV

ISLER, NEIDIGH, AND COWAN (1977)

slide17
1S0-1P1

1/2-3/2

1/2-1/2

Cu and Zn sequences to W

READER & LUTHER (1980)

the nist electron beam ion trap ebit
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

slide19
107 K plasma

EBIT Internal View

EBIT on a table top

Ion production, trapping, and excitation

http://physics.nist.gov/ebit

slide20
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

slide21
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).

slide22
Quantum Microcalorimeter
  • operates at 65 mK
  • absorber: a foil of
  • superconducting tin
  • thermistor: neutron
  • transmutation-doped
  • (NTD)germanium
slide24
EUV SPECTROMETER AT NIST EBIT

BLAGOJEVIC, LE BIGOT, ET AL. (2005)

slide30
W I & II (260 pages)

W III - LXXIV (~250 pages)

COMPILATIONS of W SPECTRA AND ENERGY LEVELS

KRAMIDA & SHIRAI (2006 & 2007)

slide31
COWAN (1977) vs. OBSERVED

IE’s SEMI-EMPIRICAL - KRAMIDA & READER (2006)

slide32
Br

Br

O

O

Ge

Ge

Ga

Ge

Ga

Zn

Zn

Zn

Cu

Cu

Cu

Cu

slide33
COUNTS

EXPERIMENT

THEORY

CR MODELING OF PLASMA OF W IN NIST EBIT -

RALCHENKO ET AL. (2007)

slide34
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)

slide35
4f

4p

4s

5f

6f

X-RAY SPECTRUM OF W WITH MICROCALORIMETER ON NIST EBIT

3d10-3d9nl

RALCHENKO ET AL. (2006)

slide36
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)

slide37
4f

4p

4s

5f

6f

X-RAY SPECTRUM OF W WITH MICROCALORIMETER ON NIST EBIT

3d10-3d9nl

RALCHENKO ET AL. (2006)

slide38
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)

slide39
CALCULATED E2:M3 RATIOS

RALCHENKO J. Phys. B: At. Mol. Opt. Phys. 40 (2007) F175

ad