Процессы гидратации в приповерхностных слоях сцинтилляторов NaI(Tl) и CsI(Na)

Abstract

The surface processes of hydration and dehydration of the surface of the scintillators NaI(Tl) and CsI(Na), which lead to the formation of so-called «dead» layer (DL) were investigated. It is shown that the dynamics of formation and structure of DL in NaI(Tl) and CsI(Na) crystals is different. The formation of DL in NaI(Tl) is the result of water adsorption by the crystals surface.   For NaI(Tl) there may be two types of DL: the  first is associated with the destruction of an activator luminescence centers, second - diffusion output of the charge carriers to the surface. The process of DL formation in CsI(Na) is prolonged and consists of two stages. The decomposition of supersaturation solid solution of vacancies proceeds at the first stage and the decomposition of activator solid solution – at the second.