Surface polishing of GSO scintillator using chemical process

A Ce doped Gd/sub 2/SiO/sub 5/, (GSO) single crystal is an excellent scintillator featuring a large light output, a short decay constant and a high absorption coefficient. It was shown in our previous studies that the surfaces of the scintillator should be polished to get scintillation light output efficiently especially for long and narrow scintillators. Therefore, we newly developed a chemical process to polish the GSO crystal. The surface of the GSO crystal was found to become smooth when it was etched using anhydrous orthophosphoric acid at 150-300/spl deg/C. The process was also proved to be applicable to large size crystal such as 20/spl times/20/spl times/200 mm/sup 3/ preventing thermal shock crack. An improvement in the scintillator efficiency was confirmed using the chemical polishing process.