GB646414A - Improvements in and relating to fluorescent luminous bodies - Google Patents

Abstract

646,414. Luminescent materials. EGYESULT IZZOLAMPA ES VILLA-MOSSAGI R.T. Sept. 15, 1948, No. 24197. Convention date, May 31, 1946. [Class 39 (i)] Fluorescent material is excited to fluorescence by the radiation of hydrogen isotope of atomic weight 3 (the so-called tritium). A vessel made with a fluorescent wall of transparent or translucent material may be filled with this gas. The vessel may be a glass ball having its inner surface coated with fluorescent material and enclosing a smaller ball, the space between the balls being filled with tritium gas. Alternatively two oppositely-disposed plane surfaces are each coated with a fluorescent coating and the space between them filled with tritium gas. The distance between the two fluorescent walls may be up to a hundred times the length of the free path of the electrons. In an example a vessel has flat walls of 1.3 metres length of side, spaced apart by 1 cm. and coated on their inner surfaces with a white fluorescent mixture of zinc sulphide and zinc cadmium sulphide, the vessel being filled with tritium gas at a pressure of 1 mm. In another construction a luminous screen is coated with a mixture comprising a solid compound of tritium and fluorescent material in the proportion of 30 mg. of tritium to 1 gr. of fluorescent material. This is distributed over a surface of from 100 to 200 sq. cm. In a modification luminescent material is suspended in a transparent compound of tritium, for example paraffin containing tritium. Alternatively, a luminescent material (preferably organic) may be dissolved in a compound of tritium, e.g. water containing tritium. This solution, or the suspension above-mentioned, is enclosed in a vessel acting as the luminous body, or it may be applied to a luminous screen. Tritium may be introduced into the luminescent material as a chemical constituent thereof, for example a hydrogen atom in any organic luminescent material may be replaced by this isotope of hydrogen. In order to protect the surrounding space against harmful effects from the radiation, the source of light may be enclosed in a lead glass container 1 mm. thick, or it may be covered with a lead glass disc.