Abstracts Book - IMRC 2018

• SE3-O015 Invited Talk
THERMALLY STIMULATED LUMINESCENCE CHARACTERIZATION
OF LiF(1-x)NaF(x) ALKALI FLUORIDE FOR RADIATION DOSIMETRY
Epifanio Cruz Zaragoza 1 , Erika Gómez Chayres 2 , Julian Marcazzó 3
1 Instituto de Ciencias Nucleares UNAM, Radiation Chemistry Department, Mexico. 2 Facultad de
Química, UNAM, Programa de Maestría y Doctorado en Ciencias Químicas, Mexico. 3 CONICET /
University of Buenos Aires, Instituto de Física, Argentina.
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 + , Ce 3+ , Eu 3+ , Lu 3+ 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 of LiNaF
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 welldefined
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 analysis of kinetics of trapping parameters of the alkali fluoride are
analyzed.