Nanostructured TLDs: Studying the impact of crystalline size on the Thermoluminescence glow-curve shape and electron trapping parameters

Abstract

Nanostructured thermoluminescent dosimeters (TLDs) and their relevance in the field of Stimulated Luminescence has grown over the past years. Particularly, since preparation methods and characterization techniques have been improved, while their integration in technological advancements which has also significantly increased. Despite the numerous case studies dealing with applications and properties of nanomaterials, there is a limited number of studies investigating cases from a basic research point of view, like studying the transition of a material from bulk to nanoscale and the dominant features of this transition. Specifically, in Thermally Stimulated Luminescence or Thermoluminescence (TL), the extensive study via geometrical signal processing with the well-established techniques of Peak Shape Methods (PSM) and Computerized Glow-Curve Deconvolution (CGCD), and the estimation of trapping parameters of certain TL peaks, along with possible dependence of the activation energy of electron traps inside the crystal structure for different crystalline sizes, are missing from the literature. The present study includes several popular TLDs like BeO, LiF, CaSO4 and other more complex crystal structures such as NaLi2PO4, K2Ca2(SO4)3, LiNaSO4 and a geological Fluorapatite in different crystalline size fractions. Special emphasis has been devoted to the estimation of activation energies and the geometrical characteristics in the nanoscale by analyzing each TL signal accordingly. While the analysis imposes several interesting cases on the implementation of the results, the study has shown that under different crystalline sizes, most of materials follow a normal downtrend on their signal with some insignificant alterations on their physical parameters.