Characteristic Features of Automated Growth of Large Scintillation Alkali Halide Single Crystals Free of Oxygen-Containing Impurities

Abstract

Influence of some oxygen-containing impurities on the spectrometric characteristics and radiation resistance of CsI(Tl) crystals has been studied. Borate-ions are shown to be no less dangerous impurity comparing to carbonate-, sulphate- and hydroxide-ions. The content of borate ions in the trace amount caused the crystal colouring under gamma-rays and light output becomes less. A method has been suggested so that the melt should be purified from impurities right when crystal are pulled therefrom automatically. Grown from the purified melt the crystals do not contain any absorption band in the IR-spectrum, which is characteristic of borate-, carbonate-, and sulphate-ions, and possess a higher radiation resistance