Abstract

Three sets of specimens were prepared in which thorium oxide contained as activators praseodymium, samarium and terbium in concentrations varying by known amounts. The specimens activated by praseodymium varied from 1 atom of praseodymium in 100 molecules of thorium oxide to 1 atom in 100,000 molecules; those activated by samarium from 1 atom in 15.5 molecules to 1 atom in 2000 molecules: those activated by terbium from 1 atom in 10 molecules to 1 atom in 40,000 molecules. The intensity of luminescence of specimens in each set was measured and the concentration of greatest brightness, the optimum concentration, determined for each of the following sources of excitation: cathode rays, ultraviolet light and hydrogen flame. The results show that the optimum concentration is different for each of the sources of excitation used. In all cases the concentration required for the optimum under cathode rays is less than that for the other methods of excitation used.

© 1935 Optical Society of America

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References

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  1. H. F. V. Little, Textbook of Inorganic Chemistry, Vol. IV, p. 297.
  2. Kowalski and Garnier, Comptes rendus 145, 391 (1909).
  3. Forsythe, J. O. S. A. 16, 307 (1928).
    [Crossref]
  4. Nichols and Howes, J. O. S. A. 22, 170 (1932).
    [Crossref]
  5. Nichols and Boardman, J. O. S. A. 20, 115 (1930).
    [Crossref]
  6. Nichols and Wick, J. O. S. A. 22, 357 (1932).
    [Crossref]
  7. Wick, Phys. Rev. 24, 272 (1924).
    [Crossref]

1932 (2)

Nichols and Howes, J. O. S. A. 22, 170 (1932).
[Crossref]

Nichols and Wick, J. O. S. A. 22, 357 (1932).
[Crossref]

1930 (1)

Nichols and Boardman, J. O. S. A. 20, 115 (1930).
[Crossref]

1928 (1)

Forsythe, J. O. S. A. 16, 307 (1928).
[Crossref]

1924 (1)

Wick, Phys. Rev. 24, 272 (1924).
[Crossref]

1909 (1)

Kowalski and Garnier, Comptes rendus 145, 391 (1909).

Boardman,

Nichols and Boardman, J. O. S. A. 20, 115 (1930).
[Crossref]

Forsythe,

Forsythe, J. O. S. A. 16, 307 (1928).
[Crossref]

Garnier,

Kowalski and Garnier, Comptes rendus 145, 391 (1909).

Howes,

Nichols and Howes, J. O. S. A. 22, 170 (1932).
[Crossref]

Kowalski,

Kowalski and Garnier, Comptes rendus 145, 391 (1909).

Little, H. F. V.

H. F. V. Little, Textbook of Inorganic Chemistry, Vol. IV, p. 297.

Nichols,

Nichols and Howes, J. O. S. A. 22, 170 (1932).
[Crossref]

Nichols and Wick, J. O. S. A. 22, 357 (1932).
[Crossref]

Nichols and Boardman, J. O. S. A. 20, 115 (1930).
[Crossref]

Wick,

Nichols and Wick, J. O. S. A. 22, 357 (1932).
[Crossref]

Wick, Phys. Rev. 24, 272 (1924).
[Crossref]

Comptes rendus (1)

Kowalski and Garnier, Comptes rendus 145, 391 (1909).

J. O. S. A. (4)

Forsythe, J. O. S. A. 16, 307 (1928).
[Crossref]

Nichols and Howes, J. O. S. A. 22, 170 (1932).
[Crossref]

Nichols and Boardman, J. O. S. A. 20, 115 (1930).
[Crossref]

Nichols and Wick, J. O. S. A. 22, 357 (1932).
[Crossref]

Phys. Rev. (1)

Wick, Phys. Rev. 24, 272 (1924).
[Crossref]

Other (1)

H. F. V. Little, Textbook of Inorganic Chemistry, Vol. IV, p. 297.

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Figures (4)

Fig. 2
Fig. 2

Brightness of luminescence of different concentrations of terbium in thorium oxide. Curve I. Hydrogen flame excitation; curve II. Cathode-ray excitation; curve III. Ultraviolet excitation.

Fig. 3
Fig. 3

Brightness of luminescence of different concentrations of samarium in thorium oxide. Curve I. Hydrogen flame excitation; curve II. Cathode-ray excitation; curve III. Ultraviolet excitation.

Fig. 4
Fig. 4

Brightness of luminescence of different concentrations of praseodymium in thorium oxide. Curve I. Hydrogen flame excitation; curve II. Cathode-ray excitation; curve III. Ultraviolet excitation.

Tables (4)

Tables Icon

Table I Terbium in thorium oxide.

Tables Icon

Table II Samarium in thorium oxide.

Tables Icon

Table III Praseodymium in thorium oxide.

Tables Icon

Table IV Optimum concentrations of different rare earths in thorium oxide. Taken from curves in Figs. 1, 2 and 3.