Abstract
This study delves into the investigation of the nature of high-temperature peaks observed in the thermally stimulated luminescence (TSL) of X-irradiated crystals of NaCl and NaCl-Li in a broad temperature range from 300 to 800 K. The research was conducted using the thermoluminescent dosimetric apparatus Harshaw 3500 (Thermo Fisher Scientific, USA). The analysis revealed high-temperature TSL peaks categorized as Type I (360÷400К) and Type II (495÷620К), which are attributed to the thermal degradation of halogen defects, specifically - and -centers, respectively. In NaCl-Li crystals, an experimental effect of increased light yield from Type II TSL peaks was observed. It intensifies with an increase in lithium concentration, and at lithium concentrations of 400 ppm intensity growth reaches two orders of magnitude higher (105→107) compared to pure NaCl crystals. The intense Type II TSL peaks (535÷570К) correlate with the increase in lithium concentration and the high-temperature incorporation of lithium into the NaCl-Li lattice. They serve as experimental evidence showcasing the efficiency of electron excitations decaying into radiation defects in the field of lithium ions under X-ray radiation exposure.