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

Abstract

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 50–250µm. K3Na(SO4)2:Eu3+(0.1%) phosphor thus obtained was given proper heat treatment (annealed at 800°C for 1h). 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 (10Gy–25kGy). 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 (10Gy–10kGy). 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.