No abstract

A Ce doped Gd,SiO, (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 "C. The process was also proved to be applicable to large size crystal such as 20~20x200 mm' preventing thermal shock crack. An improvement in the scintillator efficiency was confirmed using the chemical polishing process.

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MIS capacitors have been fabricated on (NH4)2S x -treated GaAs using a SiO x insulator prepared by conventional resistive-heating evaporation. The MIS interface state density was found to be about 1.2×1011 cm-2·eV-1 in a wide range of the band gap, which is two orders of magnitude less than that on the as-etched GaAs.

No abstract