Phase Relations around the Pyrosilicate Phase in the Gd₂O₃−Ce₂O₃−SiO₂ System

Abstract

The melting and solidification behavior of the (Gd0.9Ce0.1)2Si2O7 (Ce:GPS) which shows attractive scintillation performance was investigated by means of the slow cooling floating zone (SCFZ) method. Although Ce:GPS melts incongruently, the peritectic composition is estimated to be very close to the GPS composition, less than 67.0 mol % of SiO2 in the (Gd,Ce)2O3−SiO2 system. Constitutional supercooling occurred when approximately 70% volume of the melt was solidified, consequently, the lamellar structure consists of Ce:GPS and the amorphous phase was obtained. On the basis of our study, it is estimated that a volume of 70% of the starting material, whose composition is SiO2 = 67 mol % in the (Gd,Ce)2O3−SiO2 system at Ce 10 mol %, can be solidified as the GPS phase using top-seeded solution growth (TSSG) with the self-flux of SiO2.

Growth of bulk gadolinium pyrosilicate single crystals for scintillators

“…It was demonstrated [11] that Top Seeded Solution Growth (TSSG) technique along with the Floating zone [5] and Czochralski [6] can be applied for GPS growth. In accordance with [11], melt composition may be shifted from the stoichiometric ratio to the SiO 2 excess up to 4 mol% (concentration corresponding to the position of the peritectic point at Gd 2 O 3 -SiO 2 phase diagram [8]).…”

“…In accordance with [11], melt composition may be shifted from the stoichiometric ratio to the SiO 2 excess up to 4 mol% (concentration corresponding to the position of the peritectic point at Gd 2 O 3 -SiO 2 phase diagram [8]). At heavy doping by Ce, the average rare-earth cation radius increases in accordance with relative content of each lanthanide element [15], and position of the peritectic point relatively to the stoichiometric composition should change.…”

“…The Gd 2 O 3 -SiO 2 phase diagram modifies at high Ce concentration, so that peritectic point is situated very near to pyrosilicate composition [11]. Gadolinium pyrosilicate crystals doped with 10 at% Ce with dimensions up to |30 Â 30 mm and high light yield under g-rays and thermal neutrons were grown by Czochralski technique [6].…”

Growth and characterization of tetragonal structure modification of β-Gd2Si2O7:Ce

“…However, high Ce concentration in this method evidently should lead to concentration quenching and drop of light yield. The second approach is to crystallize GPS, or mixed pyrosilicate (LaGPS) from melt-solution with the self-flux of SiO 2 (silicon oxide concentration 71-73.6 mol.%) [17,18]. This method allows one to grow crystals with low Ce concentrations and higher luminescence intensities [19].…”

Scintillation properties of Ce doped Gd2Lu1(Ga,Al)5O12 single crystal grown by the micro-pulling-down method

“…In the last two decades, great R&D effort brought several new material systems, namely the Ce-doped orthosilicates as Gd 2 SiO 5 (GSO), Lu 2 SiO 5 (LSO), (Lu 1À x Y x ) 2 SiO 5 (LYSO), pyrosilicates based on RE 2 Si 2 O 7 (RE¼Lu, Y,Gd) and most recently LaX 3 (X¼Cl,Br) single crystal hosts, see Refs. [1][2][3][4][5][6][7][8]. The best combination of stopping power, decay time and light yield is currently achieved by Ce-activated materials.…”