Material characterisation and scintillation properties of europium activated, gadolinium lutetium oxide ceramic

Abstract

The aim of the project was to determine the role of precursor processing and ceramic microstructure on radiation response of the scintillator GLO (gadolinium lutetium oxide, activated with europium and praseodymium) through the opportunity presented by the production of UK GLO. Previous material had shown exceptional brightness but was not fully characterised in literature. GLO precursor powder has been produced using a new composition using continuous hydrothermal synthesis for the first time at University College London (UCL). This was compared to existing GLO powder produced by Nanocerox ltd for morphology and elemental composition. The lattice parameters were found to differ due to elemental composition variation between the two powders. In addition, their morphology appeared affected by production method. Material analysis was performed on the completed ceramic in order to determine the origin of scattering defects within the samples. This was done using focused ion beam liftout techniques, among others. A new form of secondary phase was discovered in the UK GLO produced with the UCLprecursor, this is enriched with Eu and has a different crystal structure than the typical secondary phases formed. The scintillator properties of the 3 UK GLO samples were studied and compared to other commmon detector materials. They were found to be extremely bright, in the case of UCL GLO sample U2a, an order of magnitude brighter than LYSO when illuminated with X-rays. The samples were also shown to have a long afterglow, although it has improved with the addition of Pr. The trapping effect causing the afterglow was theorised to be caused by a charge transfer state above the excited state in Eu3+. GLOhas been shown to be an effective and interesting scintillator material, with exceptional brightness and resolution for imaging. In the future, these findings will be used to produce novel formulations of scintillator material.

Date of Award	9 Dec 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Neil A Fox (Supervisor) & Nicholas J Bazin (Supervisor)