New, dense, and fast scintillators based on rare-earth tantalo-niobates

Samples of undoped yttrium and gadolinium tantalo-niobates with common formulae RE(NbxTa1−x)O4, where RE=Y or Gd and x=0-1, have been obtained by solid-state reaction. Systematic study of structural, luminescent, and scintillation properties of these compounds was carried out. Lattice parameters and space groups of the mixed compounds were identified. UV- and X-ray luminescence spectra, as well as relative light outputs and scintillation decay times are measured. Gadolinium tantalo-niobate with the formulae GdNb0.2Ta0.8O4 showed the light output around 13 times larger than PbWO4 and fast decay with time constant 12 ns without additional slow component. Gadolinium tantalo-niobates may be considered as promising materials for high energy physics due to extremely high density, substantial light output, and fast decay.