1. General Seminars

Dosimetric properties of LiF+MgF2 doped with Ce3+ and Eu3+ ions


Aula Seminari (LNF INFN)

Aula Seminari


Via Enrico Fermi, 40 00044 Frascati
The fluoroperovskite phosphor has interesting thermoluminescent (TL) properties and some important chemical characteristics; relatively high melting point (1070°C), low hygroscopicity, an intermediate value of the effective atomic number (Zeff~13) which is between tissue equivalent and high atomic number phosphors materials. Dosimetric properties are presents from a large batch of powder fluoride compound (LiF+MgF2) which have been doped with Ce3+[0.5mol%], Eu3+[0.4mol%]. The LiF and MgF2 salts in the stoichiometric radio (1:1) were melted by using the solid state reaction at 1080°C during 0.5 h.The syntesis was carried out in a quartz oven with constant nitrogen gas flux. Two phases in the powder samples were observed by X-ray diffraction and the mixed surface belonging to the both phases without recrystallization products were determined by SEM and the composition of the mixed compound was determined by the EDS technique. The powder samples were exposed to 0.5-180 Gy gamma doses in a Gammacell-200 irradiator, and their dosimetric properties were analyzed; i.e., dose-TL response, fading (0-60h), and TL signal reproducibility.The fading observed was about 30-40% of the whole TL signal after 24 h from irradiation.The glow curves of LiF+MgF2:Eu samples show three well defined TL peaks about 125-127, 165-168, 309-324 °C. A complex glow curve´s structure were observed when the LiF+MgF2 was doped with Ce ions; the TL glow peaks were found around 110-114, 164-169, 225-243 °C. The kinetics parameters of the glow curves have been analyzed by general order kinetics model. The dosimetric properties of the Eu and Ce ions-doped LiF+MgF2 phosphors suggest that this material could be proposed to use in gamma radiation dosimetry.