Synthesis of Bi 4 Ge 3 O 12 ceramic scintillators by the polymeric precursor method Fabiane Alexsandra Andrade de Jesus Ronaldo Santos da Silva Ze ´lia Soares Macedo Received: 2 April 2009 / Accepted: 22 April 2009 / Published online: 19 June 2009 Ó Akade ´miai Kiado ´, Budapest, Hungary 2009 Abstract Bismuth germanate ceramic powders were synthesized for the first time by the polymeric precursor method (Pechini’s method). Differential thermal analysis and thermogravimetric techniques were used to study the decomposition of the resin precursor, which indicated a suitable calcination temperature at 600 °C. It was observed that the mass loss occurs in two main stages that are associated with two exothermic reactions. The crystalline phases of the powders were inspected by the X-ray dif- fraction technique after thermal treatment between 300 and 600 °C. Single phase Bi 4 Ge 3 O 12 ceramic bodies were obtained after sintering at 840 °C for 10 h. The sintered ceramics presented a luminescence band emission centred at around 530 nm when excited with X-rays and UV radiation. Keywords Bismuth germanate Ceramic scintillators Radioluminescence Introduction Bismuth germanate (Bi 4 Ge 3 O 12 —BGO) is a synthetic material with a cubic eulytine structure, space group I 43d, containing four molecules per unit cell. This material has several interesting features such as electro-optical, electro- mechanical and scintillator properties [1, 2]. Due to this last one, BGO has been widely used as the main radiation detector in medical diagnostics, high-energy physics and in industrial applications [3]. Single crystals present high light yield (9 9 10 3 photons/MeV) and density of 7.1 g cm -3 [1], but the use of these scintillators also presents some difficulties, related to its high production cost, limited size during the growth and poor dopant distribution. For this reason, the development of BGO ceramics has been widely studied in order to obtain good scintillator properties. The advantages of using ceramics instead of single crystals are a more uniform doping and reduced costs for large sam- ples, which can be produced in a variety of shapes and sizes thus improving the scintillator applicability. Due to these attractive properties, considerable efforts have been devoted to the preparation and characterization of ceramic scintillators [2–6]. Frequently, bismuth germanate powders have been synthesized through solid state reactions using Bi 2 O 3 and GeO 2 as precursor materials [4–6]. In this method, a cal- cination temperature of 810 °C is commonly used and the powders obtained present micrometric size particles. Recently, we have reported the synthesis of BGO submi- crometric powders for the first time through the self- propagating high-temperature method (SHS—combustion synthesis) [7]. It was observed that the synthesis method did not affect the scintillator properties of the sintered ceramics. On the other hand, the polymeric precursor method (Pechini’s method) has been reported as a powerful route to obtain nanocrystalline powders in several compositions. This method allows the formation of a polymeric net (resin) containing the metallic ions homogeneously dis- tributed. The resin formation occurs in three steps: metallic chelate formation, ester formation and polyesterification [8–11]. The main advantage of this method is the good control of the stoichiometry, high purity, easy dopant incorporation and formation of nanometric or sub F. A. A. de Jesus R. S. d. Silva Z. S. Macedo (&) Grupo de Materiais Cera ˆmicos Avanc ¸ados, Departamento de Fı ´sica, Universidade Federal de Sergipe, Campus Universita ´rio, Sao Cristovao, SE 49.100-100, Brazil e-mail: zelia.macedo@gmail.com 123 J Therm Anal Calorim (2010) 100:537–541 DOI 10.1007/s10973-009-0178-1