Barium crown

Fig. 11. Index of refraction vs dispersion and optical classification of glasses. The shaded area indicates the region of glass formation. BaF = barium flint BaK = barium crown BaLF = light barium flint BaSF = heavy barium flint BK = borosilicate crown F = flint FK = fluorcrown K = crown ...

The barium crowns are usually broken into smaller pieces and can be sold in this form or cast or extmded into bars or wire. Usually the metal is packaged in argon-fiked plastic bags inside argon-fiked steel containers. Barium is classed as a flammable soHd and cannot be mailed. It should be stored in a wek-ventilated area so as to remove any hydrogen formed through reaction with water vapor. It should not be stored where contact with water is possible. 

Snitzer measured the fluorescent lifetime of neodymium in eight different glass bases. The barium crown was chosen because it gave the longest lifetime and therefore, most likely, the highest quantum efficiency. 

Decay Times (/asec) of Emission From Nd or U in Barium-Crown-Glass Powders at 300°K... 

Decay Times and Transfer Yields for Uranyl in Barium Crown Glass... 

Melamed et al. (136) describe laser oscillation in uranyl-sensitized neodymium-doped barium crown glass. They believe that the energy migrates from the uranyl to the neodymium by an electric dipole-dipole process. The results of their measurements on the uranyl lifetime, uranyl-neodymium-transfer time, and the quantum efficiency are summarized in Table VII. 

Figure 1. Index of refraction versus dispersion and optical classification of glasses shaded area indicates region of glass formation M. Plexiglas is a methyl methacrylate Lucite is an acrylic resin. BaF, barium flint BaK, Barium crown Balf, light barium flint BaSF, heavy barium flint BK, borosilicate crown F, flint FK, fluorcrown K, crown KF, crown flint LaF, lanthanum flint LaSF, heavy lanthanum flint LaK, lanthanum crown LF, light flint LLF, very light flint PK, phosphate crown PSK, heavy phosphate crown SF, heavy flint SK, heavy crown, SSK, very heavy crown, TiF, titanium flint.

Snitzer, E. (1961). Optial MASER action of Nd-l-3 in a barium crown glass. Physical Review Letters, 7(12), 444-446. 

Optical Crown Glass. Any glass of low dispersion used for optical equipment (cf. flint glass). There are many varieties, their names indicating their characteristic composition, e.g. barium crown, borosilicate crown, fluor-crown, phosphate crown, zinc crown. 

---