Synthesis, radio- and thermo- luminescence of dysprosium doped MgB4O7 under beta radiation

CRUZ-ZARAGOZA, E.; LAGORRETA-ALBA, O.; DÍAZ, D.; MARCAZZÓ, J.; CAMARILLO-GARCÍA, E.

Congreso; XXVIII International Materials Research Congress (XXVIII IMRC); 2019

The polycrystalline undoped and dysprosium-doped magnesium tetraborate, MgB4O7, phosphor wasprepared by ceramic method in the Stimulated Luminescence Laboratory of the Institute for NuclearSciences-UNAM. Magnesium tetraborate has a low effective atomic number Zeff~8.4 close to that ofbiological tissue and high sensitivity to beta radiation. This kind of low Zeff material is desirable tosearch for low dose dosimetry such as environmental and medical dosimetry. The MgB4O7 phasewas identified by XRD pattern. The magnesium tetraborate in pellets form were exposed to ionizingbeta radiation from 90Sr/90Y source. The thermoluminescence (TL) response with annealingtemperature between 100 and 550 °C was analyzed and the highest sensitivity with 1.0 and 2.0mol% of dysprosium-doped phosphor was obtained. A high intensity of glow peak at 200 °C wasobserved followed by two well defined small glow peaks at higher temperature of the glow curve.This magnesium tetraborate has an attractive simple glow peak and the linear dose response was at 1-750 mGy dose range. The radioluminescence emission of undoped phosphor shows an intenseband peaked at ~370 nm and it was ascribed to the emission of the host matrix. While thedysprosium dopant concentration increased in the lattice, the bands at 481 nm and 576 nm wasobserved and related to the dysprosium impurity in this phosphor. Therefore, the dysprosium iondopant has an important participation in the TL property of this material and it present acceptableproperties for dosimetry of ionizing radiation.