Glass-ceramics LiB3O5 – a perspective material for dosimetry

Abstract

The technology of preparation of polycrystalline lithium triborate LiB3O5 (LBO) is presented. The glass-ceramics was synthesized by solid-state reaction technique. The formation of crystallites in glass matrix is achieved through special annealing procedure that imply melting of the batch and fast cooling down of the glass followed by annealing at the crystallization temperature. The procedure allows preparing of sufficiently large number of big-sized samples. The procedure of LBO polycrystalline glass preparation is easier and much cheaper than that of LBO single crystals. The existence of the crystallites within the glass matrix was confirmed by scanning electron microscopy and X-ray diffraction studies. Comparative analysis of the X-ray diffraction patterns for both amorphous and polycrystalline LBO glass as well as for LiB3O4 single crystals indicates that the crystallites are of the micro- and nanoscale average size. The TL properties of LBO glass-ceramics were studied. It was found that polycrystalline glass LiB3O4 exhibits strong thermally stimulated luminescence after they were exposed to X-ray radiation. In particular, the samples submitted to X-ray radiation at the room temperature exhibit strong luminescence upon heating up the samples to the temperatures 376 K and 413 K. Those thermostimulated luminescence bands can be attributed to luminescent centers in boron oxide complex that forms crystal lattice of LBO. The thermostimulated dose response determined by the peak heights increases linearly with the increase of the irradiation dose. Exceptional mechanical properties of polycrystalline LBO, cheap preparation along with the linear dependence of thermostimulated luminescence response open wide perspectives for that material to be used as the detectors of any types of radiation. High abundance of 6Li and 10B isotopes also makes LBO glass-ceramics capable of neutron detection. It is important that polycrystalline lithium triborate can be exploited as tissue-equivalent material for measuring of X-ray radiation dose. Further studies will focus on improving of the thermoluminescent characteristics of LBO glass-ceramics by various dopants.