High-sensitive Caso_4:dy Thermoluminescent Phosphor Synthesis By Co-precipitation Technique

摘要

This paper describes the successful development of the co-precipitation technique for the preparation of a high-sensitive dysprosium-doped calcium sulphate (CaSO_4:Dy) thermoluminescent dosimetry (TLD) phosphor with dosimetric glow peak at ～ 230℃ which is a desired development in the field of radiation protection dosimetry. The main advantages of this co-precipitation technique over the conventional recrystallisation technique of phosphor preparation are: (ⅰ) preparation time is very less; (ⅱ) quantity of sulphuric acid evaporated is insignificant; (ⅲ) higher TL sensitivity -20% more than the present material; (ⅳ) better glow curve structure; (ⅴ) lesser glow peak shift and better linearity to gamma and (ⅵ) uniform crystal morphology and lower grain size-all grains are mostly cuboidal in shape, quite uniform and small (average size about 25 μm), suitable for manufacturing teflon discs in as-prepared form. Optimum values of various parameters in the method of preparation for a batch of 20 g CaSO_4:Dy phosphors to obtain maximum TL sensitivity, with favourable glow curves are studied.