Yavetskiy R. Radiation-induced defects in Li6-x(Na,Mg)xGd(BO3)3:Ce and Li6Gd(Y)1-xEux(BO3)3 complex borate crystals

Object of investigation - Li6Gd(BO3)3 synthesized compounds modified with Na, Mg and doped with Ce; Li6Gd(Y)1-xEux(BO3)3 (x=0-1) solid solutions and single crystals of these compositions. Aim of investigation is to study the influence of Li6Gd(BO3)3:Ce crystals modification with sodium ang magnesium on radiation defects formation processes; to determine the nature of radiation induced defects in single crystals of Li6Gd(Y)1-xEux(BO3)3 solid solutions. Methods of investigation: X-ray diffraction analysis, differential-thermal analysis, optical spectroscopy, X-ray and photoluminescence, thermally stimulated luminescence. Theoretical and practical results, novelty: The radiation induced defects caused TSL of Li6-x(Na,Mg)xGd(BO3)3:Ce modified single crystals (electron traps) and single crystals of Li6Gd(Y)1-xEux(BO3)3 solid solutions (cationic vacancy) in the Т=300-650 К temperature range have been determined. Traps depth and thermally stimulated luminescence order kinetics have been determined. It has been shown that TSL of Li6-x(Na,Mg)xGd(BO3)3:Ce crystals is caused by F+-centers decomposition with the following radiative relaxation of Ce3+ ions. It has been determined that TSL of Li6Gd(Y)1-xEux(BO3)3 crystals occurs due to thermal relaxation of lithium vacancy, forming a part of Eu2+O-VLi+ complex radiation defect, with the following radiative relaxation of Eu3+ ions. The energy storage properties of Li6Gd(Y)1-xEux(BO3)3 single crystals have been determined. The TSL yield of Li6Gd(Y)1-xEux(BO3)3 crystals is 5 times higher compared with the TLD-100 one. Application fields: high energy physics, solid state dosimetry.