Journal of Crystal Growth 242 (2002) 367–374 Influence of inclusions of intermediate tungsten oxides on characteristics of PbWO 4 scintillators S. Burachas a , S. Beloglovski a , I. Makov a , Y. Saveliev a , N. Vassilieva a , M. Ippolitov b , V. Manko b , S. Nikulin b , A. Vassiliev b , A. Apanasenko c , G. Tamulaitis d, * a North Crystals Company, Apatity, Murmansk region, Russia b RRC Kurchatov Institute, Moscow, Russia c Kharkov University, Kharkov, Ukraine d IMSAR, Vilnius University, Lithuania Received 4 February 2002; accepted 19 April 2002 Communicated by T. Hibiya Abstract Influence of phase transitions on optical and luminescence characteristics of PbWO 4 (PWO) crystals, which are utilized as scintillators in high-energy physics experiments, are studied at all stages of fabrication, including preparation of raw material, intentional doping, crystal growth, and after-growth annealing. We suggest that scintillation properties and their variations in dependence of fabrication conditions are strongly influenced by the formation of inclusions of different tungsten oxides WO 3x (0pxp1). Doping the PWO crystal with L 2 O 3 -type oxides (L=Y, La, Gd) causes replacement of the phase WO 3x by a new phase WLO, where L bounds oxygen and prevents its escape from the crystal. With these results taken into account, we reproducibly fabricate crystals with dimensions 22  22  180mm 3 ,a quantum yield of >8.5 phe/MeV, an inhomogeneity of quantum yield along the crystal of o5%, and a transmission of 25%, 55%, and 70% at wavelengths 360, 420, and 600nm, respectively. The optimized technology resulting in reproducible and stable characteristics of PWO scintillators is implemented on industrial scale at the ‘‘North Crystals’’ Company. r 2002 Elsevier Science B.V. All rights reserved. PACS: 81.10.Fq; 29.40.Mc; 61.82.Ms Keywords: A2. Czochralski method; B1. Lead tungstate; B3. Scintillators 1. Introduction Exploitation of monocrystals of PbWO 4 (PWO) as scintillators in the compact muon solenoid (CMS) experiments and the large ion collider experiment (ALICE) at CERN stimulated re- search of this crystal, optimization of techno- logy of its growth and processing, as well as motivated fabrication of PWO on industrial scale as recently reviewed in Ref. [1]. Specifications for crystals required in these projects [2] have *Corresponding author. Fax: +370-2-366059. E-mail address: gintautas.tamulaitis@ff.vu.lt (G. Tamulaitis). 0022-0248/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-0248(02)01410-0