Abstract

The method of atomic-resonance fluorescence has been applied to the detection of very small concentrations of radioactive 20Na atoms (<3 × 109 m−3). The 20Na isotope is produced by the reaction 20Ne(p, n)20Na by passing a 20 MeV proton beam through a neon gas target of density 3.5 × 1024 atoms/m3. A beam of a continuous-wave dye laser tuned to the D2 line of sodium is transmitted through the production region and the fluorescence light is detected by means of photon counting. A digital synchronous-detection technique has been applied to measure the time-dependent behavior of the 20Na atom density shortly after a proton irradiation. This behavior is determined both by radioactive decay and by diffusion of the atoms out of the production region. The absolute 20Na atom density has been estimated, using Rayleigh scattering of the laser beam on the neon gas for calibration of the optical system. The density of neutral 20Na atoms appeared to be an order of magnitude lower than the density produced. The detection method has also been used to measure the temperature dependence of saturated sodium-vapor density down to 3 × 1011 atoms/m3 (292 K).

© 1975 Optical Society of America

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References

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  1. J. D. Winefordner and T. J. Vickers, Anal. Chem. 46, 192R (1974).
    [CrossRef]
  2. L. C. J. Baghuis and H. L. Hagedoorn, Physica (Utr.) 65, 163 (1973).
    [CrossRef]
  3. F. C. M. Coolen, L. C. J. Baghuis, H. L. Hagedoorn, and J. A. van der Heide, J. Opt. Soc. Am. 64, 482 (1974).
    [CrossRef]
  4. L. C. J. Baghuis, thesis (Eindhoven University of Technology, 1974).
  5. N. Ioli and F. Strumia, in Proceedings of the International Conference on Optical Pumping and Atomic Line shape OPαLS, edited by T. Skalinski (Polskiej Akademii Nauk, Warsaw, 1969), p. 253.
  6. T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
    [CrossRef]
  7. A. V. Phelps, Phys. Rev. 114, 1011 (1959).
    [CrossRef]
  8. H. J. Besch, U. Köpf, and E. W. Otten, Phys. Lett. 25B, 120 (1967).
  9. N. Ioli and F. Strumia, J. Opt. Soc. Am. 61, 1251 (1971).
    [CrossRef]
  10. A. N. Nesmeyanov, Vapor Pressure of the Chemical Elements (Elsevier, Amsterdam, 1963), pp. 128–137.
  11. W. M. Fairbank, T. W. Hänsch, and A. L. Schawlow, J. Opt. Soc. Am. 65, 199 (1975).
    [CrossRef]

1975 (1)

1974 (2)

1973 (1)

L. C. J. Baghuis and H. L. Hagedoorn, Physica (Utr.) 65, 163 (1973).
[CrossRef]

1971 (1)

1967 (1)

H. J. Besch, U. Köpf, and E. W. Otten, Phys. Lett. 25B, 120 (1967).

1965 (1)

T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
[CrossRef]

1959 (1)

A. V. Phelps, Phys. Rev. 114, 1011 (1959).
[CrossRef]

Baghuis, L. C. J.

F. C. M. Coolen, L. C. J. Baghuis, H. L. Hagedoorn, and J. A. van der Heide, J. Opt. Soc. Am. 64, 482 (1974).
[CrossRef]

L. C. J. Baghuis and H. L. Hagedoorn, Physica (Utr.) 65, 163 (1973).
[CrossRef]

L. C. J. Baghuis, thesis (Eindhoven University of Technology, 1974).

Besch, H. J.

H. J. Besch, U. Köpf, and E. W. Otten, Phys. Lett. 25B, 120 (1967).

Coolen, F. C. M.

Fairbank, W. M.

George, T. V.

T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
[CrossRef]

Goldstein, L.

T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
[CrossRef]

Hagedoorn, H. L.

Hänsch, T. W.

Ioli, N.

N. Ioli and F. Strumia, J. Opt. Soc. Am. 61, 1251 (1971).
[CrossRef]

N. Ioli and F. Strumia, in Proceedings of the International Conference on Optical Pumping and Atomic Line shape OPαLS, edited by T. Skalinski (Polskiej Akademii Nauk, Warsaw, 1969), p. 253.

Köpf, U.

H. J. Besch, U. Köpf, and E. W. Otten, Phys. Lett. 25B, 120 (1967).

Nesmeyanov, A. N.

A. N. Nesmeyanov, Vapor Pressure of the Chemical Elements (Elsevier, Amsterdam, 1963), pp. 128–137.

Otten, E. W.

H. J. Besch, U. Köpf, and E. W. Otten, Phys. Lett. 25B, 120 (1967).

Phelps, A. V.

A. V. Phelps, Phys. Rev. 114, 1011 (1959).
[CrossRef]

Schawlow, A. L.

Slama, L.

T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
[CrossRef]

Strumia, F.

N. Ioli and F. Strumia, J. Opt. Soc. Am. 61, 1251 (1971).
[CrossRef]

N. Ioli and F. Strumia, in Proceedings of the International Conference on Optical Pumping and Atomic Line shape OPαLS, edited by T. Skalinski (Polskiej Akademii Nauk, Warsaw, 1969), p. 253.

van der Heide, J. A.

Vickers, T. J.

J. D. Winefordner and T. J. Vickers, Anal. Chem. 46, 192R (1974).
[CrossRef]

Winefordner, J. D.

J. D. Winefordner and T. J. Vickers, Anal. Chem. 46, 192R (1974).
[CrossRef]

Yokoyama, M.

T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
[CrossRef]

Anal. Chem. (1)

J. D. Winefordner and T. J. Vickers, Anal. Chem. 46, 192R (1974).
[CrossRef]

J. Opt. Soc. Am. (3)

Phys. Lett. (1)

H. J. Besch, U. Köpf, and E. W. Otten, Phys. Lett. 25B, 120 (1967).

Phys. Rev. (2)

T. V. George, L. Goldstein, L. Slama, and M. Yokoyama, Phys. Rev. 137, A369 (1965).
[CrossRef]

A. V. Phelps, Phys. Rev. 114, 1011 (1959).
[CrossRef]

Physica (Utr.) (1)

L. C. J. Baghuis and H. L. Hagedoorn, Physica (Utr.) 65, 163 (1973).
[CrossRef]

Other (3)

A. N. Nesmeyanov, Vapor Pressure of the Chemical Elements (Elsevier, Amsterdam, 1963), pp. 128–137.

L. C. J. Baghuis, thesis (Eindhoven University of Technology, 1974).

N. Ioli and F. Strumia, in Proceedings of the International Conference on Optical Pumping and Atomic Line shape OPαLS, edited by T. Skalinski (Polskiej Akademii Nauk, Warsaw, 1969), p. 253.

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Figures (5)

FIG. 1
FIG. 1

Experimental apparatus for the optical detection of 20Na isotopes. CL: cyclotron, BS: beam shutter, FC: fluorescence cell, BSP: beam stop, PB: proton beam, LB: laser beam, IF: interference filter, CS: concrete shielding, PM: photomultiplier, MCA: multichannel analyzer, TP: tape puncher, CU: control unit, CH: chopper, DL: dye laser, RT: reference tube, LIA: lock-in amplifier, CD: current digitizer, PC: preset counter.

FIG. 2
FIG. 2

The time-dependent behavior of the 20Na atoms, 40 ms after proton irradiation. The detection time per channel is 15 ms. The result was obtained from 239 production-analysis cycles.

FIG. 3
FIG. 3

Relative 20Na atom-density distribution in the fluorescence cell at the beginning of an analysis period (circles). The triangles show the intensity profile of the proton beam during the production period.

FIG. 4
FIG. 4

Experimental apparatus for the Na vapor-density measurements. DL: dye laser, CH: chopper, C: cell, O: oven, AR: aluminum oxide ring, PM: photomultiplier, LIA: lock-in amplifier.

FIG. 5
FIG. 5

Dependence of experimental values of the Na density on temperature. The triangles show the present result, the circles show the result given in Ref. 3. Line 1 is the curve given by Ioli et al. Line 2 is a least-squares fitting of the circle values and line 3 is the curve given by Nesmeyanov.

Equations (2)

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N r N f = i n g σ r i n a σ f / ( 4 π ) ,
n = j n g σ n Δ t ,