Electron spin resonance study of self-trapped holes in CdWO{sub 4} scintillator crystals

Journal Article · Sat Nov 15 00:00:00 EST 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3028228· OSTI ID:21185922

Laguta, V V ^[1]; Nikl, M; Rosa, J ^[1]; Grinyov, B V; Nagornaya, L L; Tupitsina, I A ^[2]

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1. Institute of Physics, AS CR, Cukrovarnicka 10, 162 53 Prague (Czech Republic)
2. Institute for Scintillation Materials, NASc of Ukraine, 60 Lenin Ave., 61001 Kharkov (Ukraine)

The self-trapping of holes at oxygen anions was studied by electron spin resonance in UV irradiated CdWO{sub 4} crystals. Analysis of superhyperfine interaction of the holes with {sup 183}W and {sup 111,113}Cd isotopes shows that the self-trapped hole is either delocalized in the space between two energetically equivalent nearest neighbor oxygen ions or tunnels between them. When the temperature increases above 40-50 K the self-trapped holes are thermally liberated and can be retrapped by oxygen ions perturbed by impurity ions. In case of the Nb{sup 5+} or Li{sup +} stabilizing impurities the O{sup -} centers are thermally stable up to 160-170 K. The study of kinetic characteristics of the self-trapped holes suggests that holes leave oxygen ions by thermally assisted tunneling mechanism via two slightly different channels. Corresponding ionization probabilities are defined by the Arrhenius law with an average thermal ionization energy E=90(5) meV. Calculated pre-exponential factors, about 10{sup 5} s{sup -1}, are small, which is consistent with the tunneling mechanism. Thermal stability and kinetic characteristics of the trapped holes are discussed in light of the scintillation and thermoluminescence characteristics of CdWO{sub 4}.

• OSTI ID: 21185922
• Journal Information: Journal of Applied Physics, Vol. 104, Issue 10; Other Information: DOI: 10.1063/1.3028228; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANIONS
CADMIUM 111
CADMIUM 113
CADMIUM TUNGSTATES
CRYSTALS
ELECTRON SPIN RESONANCE
HOLES
IONIZATION
ISOTOPE EFFECTS
LITHIUM IONS
NIOBIUM IONS
OXYGEN IONS
PARAMAGNETISM
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
THERMOLUMINESCENCE
TRAPPING
TUNGSTEN 183
TUNNEL EFFECT