Chapter 14 - Dosimetric properties of gamma-irradiated borate materials

Abstract

Thermoluminescence (TL) dosimetric characteristics of undoped and doped magnesium lithium borate (MLB); magnesium calcium borate (MCB); magnesium sodium borate; with dysprosium ion (10 MgO–20 Li2O; CaO; Na2O–(70-x) B2O3 –(x) Dy2O3) glasses system irradiated to Co-60 gamma-ray are presented in this study. Dy3+ ions in the range between x = 0.05 mol % to 0.7 mol % are doped to 10 MgO–20 Li2O; CaO; Na2O–70 B2O3 glasses system. The melt-quenching technique prepared the samples. Dy doped TL sample gives a better TL signal compared to the undoped sample. The Dy dopant introduces and contributes to the enhancement of the TL signal. The influence of three different modifiers (Li2O, CaO, Na2O) and dopant concentration is observed for the TL dosimetric characteristics. The glow curves reveal that the studied samples exhibit a single broad peak. The structure and morphology of the glasses were confirmed by using X-ray diffraction, differential thermal analysis, and energy dispersive X-ray analysis (EDX). MLB: 0.1 mol % Dy is the closest tissue-equivalent material from the three modifiers as its Zeff = 8.13 near Zeff of soft tissue. The MCB: 0.5 mol % Dy is the best modifier to be added to the magnesium borate glass system in its TL performance. MCB: 0.5 mol % Dy reveals the highest sensitivity compared to the other sample. Besides, MCB: 0.5 mol % Dy exhibits a low thermal fading of 30% in 42 days of storage time when exposed to intermediate low doses (5 Gy) by Co-60 gamma irradiation. MCB: 0.5 mol % Dy exhibits appreciable reproducibility behavior with no significant difference between the results of sequential measurements in the range of 0.9–1.0. MCB: 0.5 mol % Dy also satisfies most of the requirements of a good TL material. Thus, MCB: 0.5 mol % Dy could be a new potential TL material based on its superior TL properties of dose–response and low fading over other dosimetric materials for radiation dosimeter application.