Studies of ways to reduce defects in CdWO4 single crystals

Studies are reported of the nature and formation conditions of structural d efects affecting principal working characteristics of cadmium tungstate sin gle crystals (macro- and microinclusions, scattering centers, block structu re, twinning, violations of stoichiometry). It is shown that macro- and mic roinclusions are morphologically related to the crystal growth from the sup ercooled melt and are caused by the capture of crystal-forming components a s intrinsic impurities by the growing crystal. Macro- and microinclusions a re shown to form layered structures parallel to the (1 0 0) planes, which a re also twinning planes. Ways are proposed to improve structural perfection of the crystals, providing for their high functional characteristics. Acco unting for the studied features of intrinsic defect formation, optimum crys tallographic directions were suggested for the crystal growth and subsequen t cutting into scintillation elements with high and reproducible functional characteristics. (C) 1999 Elsevier Science B.V. All rights reserved.