Shpilinska O. Growing heavy-doped CsI:Tl crystals to identify charged particles by atomic number and mass

The paper proposes ways to produce heavy-doped CsI:Tl crystals (CTl> 0,15 mol.%) by anion ion (IO3- and NO2-) codopation. The scintillation characteristics of the grown crystals were studied. The influence of IO3 and NO2 ions on the functional parameters of the CsI:Tl scintillator was established. Based on the results of the study, a non-destructive method of control of IO3 and NO2 impurities was proposed. It is established that the presence of an uncontrolled technological impurity Ba2+ leads to an increase in the level of afterglow in the millisecond range in CsI:Tl crystals. It is shown that the negative effect of barium ions can be reduced due to additional doping of the ma-terial with Eu2+ - ions. A mechanism has been proposed to explain the positive role of Eu2+ ions in reducing the level of afterglow of the material. A hydrophobic protective coating based on fluoroplastic varnish, which protects the surface of the scintillator from the negative effects of the atmosphere, is proposed. The pre-treatment of the crystal surface with hecsamethyldisilazane increases the adhesion of the film to the CsI:Tl crystal and allows to increase the light output of detectors in -radiation by 21% and reduce the energy resolution from 6,28 to 4,96% by reducing the film thickness. Keywords: single crystal, cesium iodate, Stockbarger method, solid solution, scintil-lator, activator, impurity, light output, energy resolution, luminescence.