On radiation-induced optical and luminescence phenomena in thermally pretreated GSO:Ce crystals

• Main Authors: Nagornaya, L., Starzhinskiy, N., Bondar, V., Grinyov, B., Katrunov, K., Loseva, E., Onishchenko, G., Ryzhikov, V., Semynozhenko, V.
• Format: Article
• Language: English
• Published: НТК «Інститут монокристалів» НАН України 2005
• Series: Functional Materials
• Online Access: http://dspace.nbuv.gov.ua/handle/123456789/136904

Effects of thermal annealing in different gaseous media (vacuum, oxygen-containing and reductive atmospheres) upon main optical, luminescence, spectral kinetic, and scintillation characteristics of GSO:Се crystals - both subjected and not subjected to y-irradiation (10⁴-10⁶ rad) - have been studied. The heat treatment in oxygen-containing media worsens the transparence and light yield, which is explained by partial transformation of cerium ions into a state of a higher oxidation degree (Се³⁺➔Се⁴⁺), with Се⁴⁺ not involved in scintillation processes and playing the role of absorption centers for the intrinsic radiation. On the contrary, the heat treatment of GSO:Сеcrystals in vacuum may result in a certain improvement of their scintillation characteristics, probably related to the inverse transformation of the cerium charge state (Се³⁺➔Се⁴⁺). GSO:Се crystals that had been thermally pre-treated in vacuum show substantial degradation of their optical and luminescent characteristics under irradiation. This can be related to oxygen vacancies Vₒ that emerge during vacuum annealing and form F-centers under y-irradiation.