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Europium - Sinha S.P.

Sinha S.P. Europium - Springer-Verlag, 1967. - 88 p.
Download (direct link): europium1967.djvu
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As Phosphors
The fluorescence properties of europium compounds offer another possibility for using them as a red component in colour television tubes. As all fluorescence compounds are not capable of producing laser action, they still stand a chance of being used as phosphors. Those phosphors which have a main emission peak between 6110 and 6140 A are the only ones suitable. The cathodoluminescence properties of several Eu3+ doped Gd203 and YVO4 proved to be highly efficient red emittors for colour
Possible Uses and Applications of Europium
137
television [623, 669, 617], whereas Eu3+ doped Y2O3 produced more an orange hue [617, 621]. An electroluminescent phosphor CaS: Eu2+, coactivated with Cu, has been investigated by Wachtel [670]. Fok [671] has reported the afterglow of europium in a thorium oxide phosphor.
In Nucleonics
The efficient neutron absorbent materials are required to possess the following characteristics: (1) relatively high cross-section, (2) radioactive decay into daughter atoms of high cross-section after neutron absorption, (3) good resistance towards radiation damage, (4) high temperature stability, (5) ease of fabrication. Samarium, europium, gadolinium and dyprosium have high neutron absorption cross-sections, of which europium is the most effective neutron absorber. The effectiveness of europium (15% EU2O3 in stainless steel) as control rod materials is found to be 0.96 compared to the element hafnium (taken as unity), whereas samarium (2.7% Sm203 in stainless steel) has only 0.71 effectiveness. Curtis and Tharp [305] pointed out that EU2O3 could be economically used in control rods in the form of ceramics or cermets. The use of EU2O3 in stainless steel as control rods for such reactors as pressurized water, high flux boiling water, long life diphenyl coolant etc. has been suggested.
The activation [672] of Lil with Eu2+ and the use of an activated Lil phosphor as a scintillation detector for slow neutron detection [673] has been investigated. Blue, fluorescent Lil (0.03 mole % Eu) phosphor was found to be the most useful [673] phosphor because of its ease to growth, relatively high light output, chemical stability and good match with spectral characteristics of the 6260 type photomultiplier. Lil (Eu), however, does have an interfering y radiation sensitivity. Fast neutron scintillation spectra of Li6(w, a)H3 in Eu doped Lil crystals has also been investigated [674].
Diverse Applications
The ceramic properties of EU2O3 were investigated by Curtis and Tharp [305]. The electric conductivities of rare earth oxides including EU2O3 between 600—1300" C were reported [675]. The selective oxidation of Ci to C5 olefins and Ci to C5 alcohols by direct fuel cells employing noble metal anodes and aqueous H2SO4 electrolytes was found to be enhanced [676] by small additions of soluble salts of Ce, Eu and Yb.
Appendix
Isotopes of europium [677—679]
Mass number Half life Mode of decay
147 53 d Y
149 14 d Y
150 27 h P+
151 stable —
152» 5 y, 12.4 y P“
153 stable —
154 5.4 y, 16 y P~> Y
155 2(1.7)y P-.Y
156 15.11 (15.4) d P“.Y
157 15.2 (15.4) h P--Y
158 45.7 (60) m P"
159 17.9 m
a There is also a short-lived, 9.3h half life, isotope.
Values of some general physical constants
7C
Velocity of light in vacuum, c

Electronic charge, e Electronic mass, m
1 atomic mass unit, amu
1 erg
1 ev
1 joule 1 Faraday Bohr radius, do Avogadro number, N Boltzmann constant, k Planck’s constant, h
3.14159
2.9979 X 1010 cm/sec
1/6438.4696 of the wavelength of the
red line of cadmium
10-8 cm
10-4 p.
4.8030 X 10 10 absolute esu
9.1091 X 10_28 gm
0.0054860 amu
0.5110 Mev
931.5 Mev
1.660 x 10-24 erg
2.3901 X 10-8 cal
10-7 joule
10“7 watt-sec
10-7 volt-coulomb
6.2418 x 1011 ev
8066 cm-1
2306 kcal/mole
1.602 x 10-12 erg
4.1835 x 107 cal
96500 Coulombs
0.52917 A
6.0235 X 1023
1.38047 X 10-16 erg/deg.
6.624 x 10-27 erg-sec
References
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48, 1585, 1595 (1926), see also Phys. Rev. 25, 106 (1925).
3. Rolla, L., and L. Fernandes : Gazz. Chim. Паї. 56, 435, 688, 862 (1926), Atti. Acad. Lincei 4, 515 (1926).
4. Prandtl, W., and A. Grimm: Z. anorg. Chem. 136, 283 (1924).
5. Noddack, W., and Ida Tacke : Metallbörse 16,985 (1926); Chem. Zentbl.
97, (II), 12 (1926).
6. Pool, M. L., and L. I. Quill: Phys. Rev. 53, 437 (1938).
7. Marinski, J. A., and L. E. Glendenin: Chem. Engl. News 26, 2346 (1948).
8. Burbidge, E. M., and G. R. Btjrbidge: Astrophys. J. 126, 357 (1957).
9 .--W. A. Fowler, and F. Hoyle: Rev. Mod. Phys. 29, 547 (1957).
10. Cameron, A. G. W.: Physics and Chemistry of the Earth, vol. Ill, 199
(1959).
11. Taylor, S. R.: Geochim. et Cosmochim. Acta 19, 100 (1960).
12. Minami, E.: Nachr. Ges. Wiss. Göttingen, Neue Folge, 1, 155 (1935).
13. Noddack, I.: Z. anorg. Chem. 225, 337 (1935).
14. Suess, H. E., and H. C. Urey: Rev. Mod. Phys. 28, 53 (1956).
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