On the development on scintillation materials operating at high temperature

Abstract

High light yield and its stability at high temperature are required conditions to exploit scintillation material for a well logging applications. High light yield causes sensitivity and expressivity of the measurements and its stability at high temperature gives an opportunity to simplify design of well logging tools. A combination of high light yield and its stability at high temperature in the material occurs not too often and depends on the favourable concurrence of the properties of the matrix host and luminescent centre. Among all scintillation materials available the most promising are those which scintillation properties aie due to Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> and Pr <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> activating ions. They emit fast and high light yield scintillation due to interconfiguration luminescent transitions 5d → f(Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> ) 4f5d → f <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (Pr <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> ). In this article we discuss factors which affect temperature dependence of light yield of Pr and Ce doped scintillation materials. The influence of the processes of nonradiative quenching and thermoionisation on the temperature dependence of scintillation yield are analysed. It is concluded that Pr <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> activator has higher potential to construct scintillators capable to operate at high temperature.