Salient Features in the Preparation of Promethium-147 Activated Zinc Sulphide Phosphor Light Sources

Activation of zinc sulphide phosphor with beta radiation of ¹⁴⁷Pm will provide self-sustaining light sources and are widely used as nocturnal illumination devices. Use of ¹⁴⁷Pm as energy source is most promising since it forms non-volatile salts. By virtue of this property, it has been precipitated as hydroxide from its aqueous solution for in situ deposition on zinc sulphide phosphor. In this paper, the details of various reaction parameters such as the rate of deposition of ¹⁴⁷Pm(OH)₃ on ZnS, duration of shaking, specific activity of phosphor and effect of fatty acid (additive) concentration versus luminosity are illustrated with experimental evidence so as to obtain, under optimum conditions, an overall luminosity of 1000 micro lamberts (lm).