Effect of pH on lyoluminescence of K₃Na(SO₄)₂:Eu³⁺ phosphor for its application in dosimetry of high-energy radiations

Lyoluminescence (LL) of microcrystalline K₃Na(SO₄)₂:Eu³⁺ was studied for different doses and for different pH values of solvents. The material was prepared by a simple melt method and was then crushed and sieved to get particle sizes in different ranges between 50–250 µm. K₃Na(SO₄)₂:Eu³⁺(0.1%) phosphor thus obtained was given proper heat treatment (annealed at 800 °C for 1 h). It was then irradiated with γ rays from ⁶⁰Co radioactive source to study its LL characteristics and the effect of pH of the solvent on LL intensity. The glow (decay) curves, dose response and variation of the LL intensity with pH were studied for different doses (10 Gy–25 kGy). pH of the solutions used for studying LL was varied in the range of 0.55–13.0 using different diluted acids (i.e., H₂SO₄, HCl and HNO₃) and alkalies (i.e., LiOH, NaOH and KOH) solutions. The LL intensity was not only found to vary with the net pH of the solution used for taking LL but also with the different acids/alkalies used for varying the pH. This has a great importance in radiation dosimetry using LL as the user needs to know which solution is best suited. The material shows linear dose response for a broad range of doses (10 Gy–10 kGy). It was also observed that the fading of the LL intensity is more if the material is exposed to room light than its storage in dark. Very wide dose range, high-sensitivity and low fading make the material suitable for dosimetry of high-energy radiations using LL technique. - Highlights: • Simple method of material preparation. • Variation of LL intensity with particle size. • Very wide dose response to ionizing radiation. • Effect of pH using different acids/alkalies on LL. • Effect of room light on fading.