Thermoluminescence properties of strontium-copper co-doping lithiun-borate glass for ionizing radiation application

Abstract

Thermoluminescent dosimetry (TLD) has become a reliable and promising method used in ionizing radiation-dose measurements nowadays. There are wide range of TLD materials in use and among them the glassy matrix structure represents a potentially attractive system due to the outstanding properties such as good thermal stability, human tissue equivalent properties, relatively low cost, easily shaped and good ability to host luminescent activators in elevated concentrations. Many efforts have been devoted to develop tissue equivalent suitable glassy scintillator materials for ionizing radiation measurements. The aim of the present studies was to determine the influences of dopant (SrCO3) and co-dopant (Cu2O, Mg2O, Na2O, P2O2) on lithium-borate (LB) glasses upon their physical, structure, thermal and TLD properties. Six series of glass compositions xLi2CO3–(100-x)H3BO3, 15Li2CO3–(85–y)H3BO3–ySrCO3,15Li2CO3–(83–z)H3BO3–2SrCO3–zCu2O, 15Li2CO3–(83–u)H3BO3–2SrCO3–uMg2O, 15Li2CO3–(83–v)H3BO3–2SrCO3–vNa2O and 15Li2CO3–(83–w)H3BO3–2SrCO3–wP2O2 with varying concentrations of x, y, z, u, v, w (in mol%) were synthesized using melt quenching technique. The amorphous phase, structure, composition, morphologies, thermal and physical properties of synthesized glass samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Energy-dispersive X-ray (EDX) spectroscopy, Field emission scanning electron microscope (FESEM) and Differential thermal analysis (DTA) respectively. The TLD properties were measured in terms of thermoluminescence (TL) response, sensitivity, linearity, fading, reusability, minimum detectable dose, and Z-effective. These synthesized glass systems were exposed to various types of ionizing radiations such as Co-60 gamma ray, 6 and 10 MeV electrons, 6 and 10 MV X-ray photons. The XRD patterns confirmed the true amorphous state of all prepared glass samples. The FTIR results show that the structure of the glass samples is that of LB glass. The dopant (SrCO3) and co-dopant (Cu2O) in LB glass were not changing the main feature of the structure. The EDX analyses of samples show that the composition of the glasses is that of LB, its doped and co-doped. The FESEM results show homogeneous morphology. The DTA shows that the prepared glass samples are physically and thermally stable. Samples doped with 2.0 mol% of SrCO3 and 0.01 mol% of Cu2O concentration showed the highest TL efficiency. Furthermore, the co-doped glasses exhibited very significant TL properties such as linear dose response, good reusability, low minimum detectable dose and high sensitivity. The samples also showed good dose linearity characteristic and TL sensitivity in the dose range of 0.5-4.0 Gy when irradiated with 10 MeV electrons. The achieved effective atomic number of glass samples was found to be 9.69 and 11.08 for LB doped with 2.0 mol% of SrCO3 and co-doped with 0.01 mol% of Cu2O, respectively. The relative energy response of both doped and co-doped samples have been calculated theoretically and the results obtained are in good agreement with the experimental ones. In conclusion, the studied glass samples were found to have excellent properties required in TLD applications.