Synthesis and investigation of the luminescent properties of carbon doped lanthanum aluminate (LaAlO3) for application in radiation dosimetry

• LaAlO3:C crystals were synthesized under highly reducing atmosphere.
• The undoped LaAlO3 showed high thermoluminescent sensitivity to UV photons.
• They have great potential to be investigated for dosimetry purposes.

LaAlO3 single crystals grown under hydrothermal conditions and co-doped with Ce and Dy atoms have been recently reported to show high thermoluminescent (TL) outputs for ultraviolet (UV) radiation fields (Oliveira et al., 2011). Due to this property, they have been considered for further investigation for applications in UV dosimetry. Encouraged by these results, we start an investigation about the TL properties of polycrystalline LaAlO3 grown by an alternative method. In this method, equimolar amounts of Al2O3 and La2O3 are sintered, producing polycrystalline LaAlO3 powder. Polycrystals doped with amounts of carbon ranging from 0.0 to 5.0 at.% were synthesized by sintering under hydrogen reducing atmosphere. After irradiation with a UV commercial lamp, the best TL outputs were observed for the undoped sample. The recorded TL glow curves show a main TL peak centered at 175 °C. The TL emission spectrum show a broad emission peak centered at 634 nm and another three narrow peaks centered at 724 nm, 738 nm and 754 nm, respectively. The undoped material show a huge TL output response for UV spectral irradiances ranging from 0.04 to 1.68 mJ cm−2 that can be fitted by a 2nd order polynomial regression. The investigation demonstrates that undoped polycrystalline LaAlO3 crystals sintered under reducing atmosphere are very attractive to be investigated as high sensitivity ultraviolet TL dosimeters.