Etching studies on lutetium yttrium orthosilicate LuxY2-xSiO5:Ce (LYSO) scintillator crystals

Surface dissolution has been investigated on {100}, {010}, {001}, {110} and {101} oriented Lu1.6Y0.4SiO5:Ce crystal samples by using orthophosphoric acid up to 180 deg. C. Depending on the etching temperature and surface orientation smooth or bunched surfaces were produced. In order to study the effect of the etching process on the scintillation properties temperature dependent optical absorption measurements were carried out up to 236 deg. C. It was found that depending on the post-growth history of the sample, etching may influence the scintillation mechanism by modifying the concentration of shallow traps.