Application of alumina nanoparticles in thermoluminescence dosimetry

Abstract

Today, it has become important to measure the dose that a person is exposed to in the work environment [1-2]. Considering the importance of this issue and as a result of dosimetry and radiation protection, thermoluminescence is one of the most effective practical methods for dosimetry applications . Thermoluminescence is a luminescence phenomenon, and luminescence excitations in materials can be created by various types of sources such as ultraviolet rays, electric fields (electroluminescence), cathode rays (cathodeluminescence), etc. [3]. When the materials are irradiated for the thermoluminescence phenomenon, the energy of the beam is excited by the electrons of the valence layer of the charge carriers, and they are separated from their alignment, thus beginning to move freely throughout the crystal lattice to finally reach the trap points caused by lattice imperfections or impurities. In fact, they are created in the host substance and get trapped. Accordantly, the energy of the radiated rays is stored in the material, so that the trapped charge carriers are excited and released from the dopant centers by heat [4]. The transition of electrons and holes from the trapping levels to their ground state leads to photon emission. These photons have the extra energies released by charge carriers. On the other hand, materials in nanodimensions show behavior and characteristics that will induce different properties compared with the bulk state [5]. In other words, nanotechnology has created a clear perspective for us in this field, and today the study of the properties of nanomaterials has become one of the research topics [6]. Alumina structure with heat resistance is used to make flame retardant coatings in fire extinguishers. At the nanoscale, alumina nanoparticles are used as an electrical insulator and as a very high thermal conductor due to their hardness. Alumina nanoparticles are also employed as one of the biomaterials in the medical and health industries to replace hip joints [7]. In this research, alumina nanoparticles are synthesized by a sol-gel method, and their dosimetric properties are studied.