Influence of synthesis conditions (evaporation temperature, annealing and ph) in the thermoluminescence response of undoped and doped Ce³⁺, K⁺ Na₄P₂O₇

The investigation of materials with properties to estimate and quantify the ionizing radiation dose has been increased significantly in the last two decades, particularly due to the use of ionizing radiation in medical treatments, production of electricity, and food industry. Materials in this field must overcome several requirements, including wide interval where the response is linear with the absorbed dose, high sensitivity, low fading, an isolated peak, chemically inert, among others. Thermoluminescence (Tl) phenomena has been widely used for decades in radiation dosimetry field. Phosphates and their derivatives have been proposed, in recent years, for low-dose studies due to their accuracy in the detection of ionizing radiation and their low production cost. Several pyrophosphates, such as calcium, sodium, and strontium, have exhibited very well Tl properties. Sodium pyrophosphate doped with Dy²⁺ has previously been proposed as a thermoluminescent dosimeter. However, the Tl response of the undoped material and the factors involved in its production remain largely unexplored. In this study, we synthesized Na₄P₂O₇ using the evaporating solvent method and analyzed the effects of evaporation temperature, annealing temperature, and ph on the thermoluminescent response of the material. The synthesized materials were irradiated at 1 Gy using a strontium/yttrium-90 beta source. Multiple Tl glow curves were measured to observe the formation of intensity maxima at 60°C, 125°C, and 150 °C. Furthermore, we investigated the effects of the incorporation of Ce³⁺ and K⁺ ions at 1% mol on the Tl response of Na₄P₂O₇. The optimal synthesis conditions were determined to be an evaporation temperature of 150 °C, an annealing temperature of 900 °C for 6 hours, and a ph of 10, resulting in a fivefold improvement in Tl intensity. However, the addition of Ce³⁺ and K⁺ negatively affects the Tl response. The optimization of synthesis conditions in the evaporation method could contribute to the production of a Na₄P₂O₇ material with interesting properties for its potential application in radiation dosimetry. (author)