Thermally stimulated luminescence characterization of LiF(1-x)NaF(x) alkali fluoride for radiation dosimetry

CRUZ-ZARAGOZA, E.; GÓMEZ-CHAYRES, E.; MARCAZZÓ, J.

Cancun

Congreso; XXVII International Materials Research Congress (XXVII IMRC); 2018

Sociedad Mexicana de Materiales

The alkali fluorides compounds are being prepared by different methods and they have good radiation sensitivity that makes useful to radiation dosimetry in environment of nuclear reactor application or in research of low radiation fields. The LiF(1-x)NaF(x) phosphor system and it doped with rare earth ions were synthesized by solid state reaction. The phosphors were doped with different ions: Tl+, Ce3+, Eu3+, Lu3+ in order to investigated their thermoluminescence (TL) property. The LiF and NaF phases were identified by powder XRD, and the characterization of the surface and chemical composition were analyzed by optical microscope imaging and using SEM. Different compositions ofLiNaF were investigated to the effect of cation concentration on the TL properties. Samples of selected particle sizes ((R)) at different doses. The dose rate was kept constant during all the experiments, and for the glow curve acquisition a constant heating rate was used. The glow curves from the raw materials, pure LiF and NaF, it was observed multiple overlapped glow peaks mainly ascribed to the lattice of the compounds. For the lithium halide, an intense peak at 270 °C is the main characteristic of the glow curve, while for the sodium halide a well-defined and intense peak at 220 °C and followed by other multiple broad peaks are forming the glow curve. On the other hand, for the mixed system with sodium concentration below 75 mol%, a single peak at 120 °C is observed, with small shoulders at higher temperatures. Within the composition range of solid state solubility (above 92 mol% of sodium fluoride), the cooling rate has an important role on glow curve definition, giving insights of the lithium ion participation on the luminescent phenomena. However, at intermediate compositions of the mixed system have a good linear dose-response between 50mGy and 1 Gy of gamma doses. The abroad glow curves obtained in the LiNaF system can be related to the dopants ions and intrinsic defects in the phosphor. The nalysis of kinetics of trapping parameters of the alkali fluoride are analyzed.