Abstract

The isotopic enrichment of copper ions in a positive column Cu–Ne discharge using optogalvanic excitation is analyzed with a rate equation model. With excitation at 510.6 nm, the fraction of the ions belonging to the 63-amu isotope of copper is enriched relative to the neutral abundance. Enrichment as large as 10% is calculated when the initial abundance of the neutral isotope is small (≤0.1) and the discharge current density is large (≥75 mA/cm2). The degree of enrichment is examined as a function of the initial abundance, discharge current, the rate of charge exchange, and the diameter of the discharge tube.

© 1983 Optical Society of America

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  1. W. B. Bridges, J. Opt. Soc. Am. 68, 352 (1978).
    [CrossRef]
  2. R. B. Green, R. A. Keller, G. G. Luther, J. C. Travis, Appl. Phys. Lett. 29, 727 (1976).
    [CrossRef]
  3. R. A. Keller, R. Engleman, E. F. Zalewski, J. Opt. Soc. Am. 69, 738 (1979).
    [CrossRef]
  4. R. Shuker, A. Ben-Amar, G. Erez, Opt. Commun. 42, 29 (1982).
    [CrossRef]
  5. J. E. M. Goldsmith, Appl. Phys. B 28, 304 (1982).
  6. E. F. Zalewski, R. A. Keller, C. T. Apel, Appl. Opt. 20, 1584 (1981).
    [CrossRef] [PubMed]
  7. C. Dreze, Y. Demers, J. M. Gagne, J. Opt. Soc. Am. 72, 912 (1982).
    [CrossRef]
  8. R. A. Keller, E. F. Zalewski, Appl. Opt. 19, 3301 (1980).
    [CrossRef] [PubMed]
  9. B. E. Warner, K. B. Person, J. Appl. Phys. 50, 5964 (1979).
    [CrossRef]
  10. D. M. Pepper, J. Quantum Electron. QE-14, 971 (1978).
    [CrossRef]
  11. M. Maeda, Y. Nomiyama, Y. Miyazoe, Opt. Commun. 39, 64 (1981).
    [CrossRef]
  12. M. J. Kushner, J. Quantum Electron. QE-17, 1555 (1981).
    [CrossRef]
  13. A. Z. Msezane, R. J. W. Henry, “Electron Impact Excitation of Atomic Copper,” in Proceedings, Twelfth International Conference of Physics of Electronic and Atomic Collisions, Gatlinburg, Tenn. (1981), pp. 176–177; R. J. W. Henry, Department of Physics, Louisiana State U.; private communication (1981).
  14. N. Winter, A. Hazi, “Review of Electron Impact Excitation Cross Sections for Copper Atom,” Lawrence Livermore National Laboratory; UCID-19314 (1982).
  15. T. Resigno, Lawrence Livermore National Laboratory, private communication (1981).
  16. C. Deutsch, J. Appl. Phys. 44, 1142 (1973).
    [CrossRef]
  17. L. J. Kieffer, “A Compilation of Electron Cross Section Data for Modeling Gas Discharge Lasers,” J. Inst. Lab. Astrophys. Rep. COM-74-1161 (1973).
  18. B. E. Cherrington, IEEE Trans. Electron Devices, ED-26, 148 (1979).
    [CrossRef]
  19. N. M. Nerheim, J. Appl. Phys. 48, 3244 (1977); N. M. Nerheim, C. J. Chen, “Final Report—Phase I Visible Wavelength Laser Development,” DARPA 2756Jet Propulsion Laboratory, Pasadena, Calif. (Aug.1975).
    [CrossRef]
  20. Exploitation of the difference in the rate of ambipolar diffusion for different isotopes in a longitudinal DC discharge has itself been suggested as an enrichment technique. See, for example, A. I. Karchevskii, E. P. Potanin, Sov. J. Phys. 8, 101 (1982).

1982

R. Shuker, A. Ben-Amar, G. Erez, Opt. Commun. 42, 29 (1982).
[CrossRef]

J. E. M. Goldsmith, Appl. Phys. B 28, 304 (1982).

Exploitation of the difference in the rate of ambipolar diffusion for different isotopes in a longitudinal DC discharge has itself been suggested as an enrichment technique. See, for example, A. I. Karchevskii, E. P. Potanin, Sov. J. Phys. 8, 101 (1982).

C. Dreze, Y. Demers, J. M. Gagne, J. Opt. Soc. Am. 72, 912 (1982).
[CrossRef]

1981

E. F. Zalewski, R. A. Keller, C. T. Apel, Appl. Opt. 20, 1584 (1981).
[CrossRef] [PubMed]

M. Maeda, Y. Nomiyama, Y. Miyazoe, Opt. Commun. 39, 64 (1981).
[CrossRef]

M. J. Kushner, J. Quantum Electron. QE-17, 1555 (1981).
[CrossRef]

1980

1979

R. A. Keller, R. Engleman, E. F. Zalewski, J. Opt. Soc. Am. 69, 738 (1979).
[CrossRef]

B. E. Cherrington, IEEE Trans. Electron Devices, ED-26, 148 (1979).
[CrossRef]

B. E. Warner, K. B. Person, J. Appl. Phys. 50, 5964 (1979).
[CrossRef]

1978

D. M. Pepper, J. Quantum Electron. QE-14, 971 (1978).
[CrossRef]

W. B. Bridges, J. Opt. Soc. Am. 68, 352 (1978).
[CrossRef]

1977

N. M. Nerheim, J. Appl. Phys. 48, 3244 (1977); N. M. Nerheim, C. J. Chen, “Final Report—Phase I Visible Wavelength Laser Development,” DARPA 2756Jet Propulsion Laboratory, Pasadena, Calif. (Aug.1975).
[CrossRef]

1976

R. B. Green, R. A. Keller, G. G. Luther, J. C. Travis, Appl. Phys. Lett. 29, 727 (1976).
[CrossRef]

1973

C. Deutsch, J. Appl. Phys. 44, 1142 (1973).
[CrossRef]

Apel, C. T.

Ben-Amar, A.

R. Shuker, A. Ben-Amar, G. Erez, Opt. Commun. 42, 29 (1982).
[CrossRef]

Bridges, W. B.

Cherrington, B. E.

B. E. Cherrington, IEEE Trans. Electron Devices, ED-26, 148 (1979).
[CrossRef]

Demers, Y.

Deutsch, C.

C. Deutsch, J. Appl. Phys. 44, 1142 (1973).
[CrossRef]

Dreze, C.

Engleman, R.

Erez, G.

R. Shuker, A. Ben-Amar, G. Erez, Opt. Commun. 42, 29 (1982).
[CrossRef]

Gagne, J. M.

Goldsmith, J. E. M.

J. E. M. Goldsmith, Appl. Phys. B 28, 304 (1982).

Green, R. B.

R. B. Green, R. A. Keller, G. G. Luther, J. C. Travis, Appl. Phys. Lett. 29, 727 (1976).
[CrossRef]

Hazi, A.

N. Winter, A. Hazi, “Review of Electron Impact Excitation Cross Sections for Copper Atom,” Lawrence Livermore National Laboratory; UCID-19314 (1982).

Henry, R. J. W.

A. Z. Msezane, R. J. W. Henry, “Electron Impact Excitation of Atomic Copper,” in Proceedings, Twelfth International Conference of Physics of Electronic and Atomic Collisions, Gatlinburg, Tenn. (1981), pp. 176–177; R. J. W. Henry, Department of Physics, Louisiana State U.; private communication (1981).

Karchevskii, A. I.

Exploitation of the difference in the rate of ambipolar diffusion for different isotopes in a longitudinal DC discharge has itself been suggested as an enrichment technique. See, for example, A. I. Karchevskii, E. P. Potanin, Sov. J. Phys. 8, 101 (1982).

Keller, R. A.

Kieffer, L. J.

L. J. Kieffer, “A Compilation of Electron Cross Section Data for Modeling Gas Discharge Lasers,” J. Inst. Lab. Astrophys. Rep. COM-74-1161 (1973).

Kushner, M. J.

M. J. Kushner, J. Quantum Electron. QE-17, 1555 (1981).
[CrossRef]

Luther, G. G.

R. B. Green, R. A. Keller, G. G. Luther, J. C. Travis, Appl. Phys. Lett. 29, 727 (1976).
[CrossRef]

Maeda, M.

M. Maeda, Y. Nomiyama, Y. Miyazoe, Opt. Commun. 39, 64 (1981).
[CrossRef]

Miyazoe, Y.

M. Maeda, Y. Nomiyama, Y. Miyazoe, Opt. Commun. 39, 64 (1981).
[CrossRef]

Msezane, A. Z.

A. Z. Msezane, R. J. W. Henry, “Electron Impact Excitation of Atomic Copper,” in Proceedings, Twelfth International Conference of Physics of Electronic and Atomic Collisions, Gatlinburg, Tenn. (1981), pp. 176–177; R. J. W. Henry, Department of Physics, Louisiana State U.; private communication (1981).

Nerheim, N. M.

N. M. Nerheim, J. Appl. Phys. 48, 3244 (1977); N. M. Nerheim, C. J. Chen, “Final Report—Phase I Visible Wavelength Laser Development,” DARPA 2756Jet Propulsion Laboratory, Pasadena, Calif. (Aug.1975).
[CrossRef]

Nomiyama, Y.

M. Maeda, Y. Nomiyama, Y. Miyazoe, Opt. Commun. 39, 64 (1981).
[CrossRef]

Pepper, D. M.

D. M. Pepper, J. Quantum Electron. QE-14, 971 (1978).
[CrossRef]

Person, K. B.

B. E. Warner, K. B. Person, J. Appl. Phys. 50, 5964 (1979).
[CrossRef]

Potanin, E. P.

Exploitation of the difference in the rate of ambipolar diffusion for different isotopes in a longitudinal DC discharge has itself been suggested as an enrichment technique. See, for example, A. I. Karchevskii, E. P. Potanin, Sov. J. Phys. 8, 101 (1982).

Resigno, T.

T. Resigno, Lawrence Livermore National Laboratory, private communication (1981).

Shuker, R.

R. Shuker, A. Ben-Amar, G. Erez, Opt. Commun. 42, 29 (1982).
[CrossRef]

Travis, J. C.

R. B. Green, R. A. Keller, G. G. Luther, J. C. Travis, Appl. Phys. Lett. 29, 727 (1976).
[CrossRef]

Warner, B. E.

B. E. Warner, K. B. Person, J. Appl. Phys. 50, 5964 (1979).
[CrossRef]

Winter, N.

N. Winter, A. Hazi, “Review of Electron Impact Excitation Cross Sections for Copper Atom,” Lawrence Livermore National Laboratory; UCID-19314 (1982).

Zalewski, E. F.

Appl. Opt.

Appl. Phys. B

J. E. M. Goldsmith, Appl. Phys. B 28, 304 (1982).

Appl. Phys. Lett.

R. B. Green, R. A. Keller, G. G. Luther, J. C. Travis, Appl. Phys. Lett. 29, 727 (1976).
[CrossRef]

IEEE Trans. Electron Devices

B. E. Cherrington, IEEE Trans. Electron Devices, ED-26, 148 (1979).
[CrossRef]

J. Appl. Phys.

N. M. Nerheim, J. Appl. Phys. 48, 3244 (1977); N. M. Nerheim, C. J. Chen, “Final Report—Phase I Visible Wavelength Laser Development,” DARPA 2756Jet Propulsion Laboratory, Pasadena, Calif. (Aug.1975).
[CrossRef]

C. Deutsch, J. Appl. Phys. 44, 1142 (1973).
[CrossRef]

B. E. Warner, K. B. Person, J. Appl. Phys. 50, 5964 (1979).
[CrossRef]

J. Opt. Soc. Am.

J. Quantum Electron.

D. M. Pepper, J. Quantum Electron. QE-14, 971 (1978).
[CrossRef]

M. J. Kushner, J. Quantum Electron. QE-17, 1555 (1981).
[CrossRef]

Opt. Commun.

M. Maeda, Y. Nomiyama, Y. Miyazoe, Opt. Commun. 39, 64 (1981).
[CrossRef]

R. Shuker, A. Ben-Amar, G. Erez, Opt. Commun. 42, 29 (1982).
[CrossRef]

Sov. J. Phys.

Exploitation of the difference in the rate of ambipolar diffusion for different isotopes in a longitudinal DC discharge has itself been suggested as an enrichment technique. See, for example, A. I. Karchevskii, E. P. Potanin, Sov. J. Phys. 8, 101 (1982).

Other

L. J. Kieffer, “A Compilation of Electron Cross Section Data for Modeling Gas Discharge Lasers,” J. Inst. Lab. Astrophys. Rep. COM-74-1161 (1973).

A. Z. Msezane, R. J. W. Henry, “Electron Impact Excitation of Atomic Copper,” in Proceedings, Twelfth International Conference of Physics of Electronic and Atomic Collisions, Gatlinburg, Tenn. (1981), pp. 176–177; R. J. W. Henry, Department of Physics, Louisiana State U.; private communication (1981).

N. Winter, A. Hazi, “Review of Electron Impact Excitation Cross Sections for Copper Atom,” Lawrence Livermore National Laboratory; UCID-19314 (1982).

T. Resigno, Lawrence Livermore National Laboratory, private communication (1981).

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Figures (6)

Fig. 1
Fig. 1

Species included in this analysis. A set of copper levels is included for both copper isotopes. The stimulating radiation at 510.6 nm is between the 2D5/2 and 2P3/2 states.

Fig. 2
Fig. 2

Ion enrichment factor β for the 63-amu isotope of copper as a function of discharge current and initial neutral abundance of that isotope. The diameter of the discharge tube is 1 cm.

Fig. 3
Fig. 3

Typical discharge parameters and OGE for the conditions of Fig. 2 and an initial 63-amu abundance of 0.3. The top figure shows conditions in the absence of the 510.6-nm radiation. The lower figure shows the change in electron density, electron temperature, and discharge voltage resulting from the presence of saturating 510.6-nm radiation. The electron temperature remains within a few percent of 1.2 eV for all current densities in the absence of the laser radiation.

Fig. 4
Fig. 4

Ion enrichment factor for the 63-amu copper isotope as a function of the value of the copper ion–copper charge exchange cross section and the initial neutral abundance of the 63-amu isotope. The current density was 25 mA/cm2. The ion enrichment factors for low initial abundances are less sensitive to the deleterious effects of charge exchange.

Fig. 5
Fig. 5

Ion enrichment factor for the 63-amu isotope as a function of the radius of the discharge tube with and without saturating 510.6-nm radiation. The initial neutral abundance was 0.5, and the current density was held constant at 30 mA/cm2. The extremum in β, as the discharge tube radius increases results from competition between decreasing ion losses due to diffusion and increasing ion mixing from charge exchange collisions as the discharge tube radius increases. The charge exchange rate is proportional to the square of the ion density (also shown).

Fig. 6
Fig. 6

Fraction of atoms of the 63-amu copper isotope in the 2P1/2, 2D5/2, and 2P3/2 states as a function of the average intensity of radiation at 324.8 nm (2S1/22P3/2). (Is is the saturation intensity.) The increasing fraction of atoms in the 2D5/2 state reduces the contribution of stepwise ionization of this isotope relative to the unexcited isotope.

Equations (6)

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N s j k t = l N s l k r s l j n e - l N s j k r s j l n e + n l , m N s m n N s l k r s l m j - n l , m N s l n N s j k r s j l m - N s j k ( N m r P I + N + r C E ) - D s k N s j Λ 2 + n e N s I k ( r r r + n e r c r r ) - l ( N s j k - g s j g s l N s l k ) B s j l k I s j l k - N s j k τ s j .
N s I k t = l N s l k r s l I n e + l ( N m r P I + N + r C E ) N s l k + n l , m N s l k N s m n r s l m I - n l N s l n N s I k r s l C E + n l N s I n N s l k r s l C E - N s I k n e ( r r r + r c r r n e ) - D s a k N s I k Λ 2 .
T e t = 2 3 e 2 E 2 m e l ν c l - l ( 2 m e ) M ν c l ( T e - T g ) - s m > l 2 3 ɛ s l m N s l r s l m + s m < l 2 3 ɛ s l m N s l r s l m .
T g = T w + j E R 2 h
E = I o 1.36 n e R 2 μ e e
β i = f I i / f N i - 1.0

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