Production of bismuth germanate ceramic scintillators by combustion synthesis route

Abstract

The present work presents the results from production of ceramic scintillator Bi4Ge3O12 (bismuthgermanate – BGO), which is very sensitive to beta, gamma and X-rays. The production route adopted wascombustion synthesis. In this route, the precursors germanium oxide and bismuth nitrate were mixed tourea, used as fuel, and heated up to the ignition temperature, 500 °C. The ignition starts an exothermicreaction that promotes the formation of the desired crystalline phase. It was observed a dependency of theagglomeration of the synthesized powders upon the pH of the initial mixture. The pH was controlledthrough the addition of ammonium dioxide, and was varied from zero up to 9. Intermediate crystallinephases were observed by DRX measurements of the product of the combustion reaction. After calcinationat 600 °C/24 h, the Bi12GeO20 content was enhanced. The optimum conditions of synthesis andsinterization of the samples were determined through auxiliary techniques such as DTA and SEM. Thesynthesized powders presented particle size near 10 nm, whereas the sintered grains reached near 2 μm.The relative density of sintered ceramics, obtained from Archimedes’ method, was 96%.