The luminescence of PbWO4:Tb and CdWO4:Tb,Li crystals at synchrotron excitation

The luminescence of PbWO4:Tb³⁺ and CdWO4:Tb,Li crystals is effectively excited by the synchrotron radiation in the long-wavelength fundamental absorption edge region and in the region of photon multiplication. In the case of PbWO4:Tb³⁺ excitation of using photons with energy 14.1 eV the weak recombination luminescence of terbium impurity is observed against the background of matrix emission at 300 K. The luminescence intensity of PbWO4:Tb³⁺ increases about an order of magnitude, when the temperature is decreased to 8 K, at the same time the luminescence characteristic for PbWO4 crystals is observed. It was shown, that the spectrum of low-temperature matrix luminescence of PbWO4:Tb is approximated by elementary bands with maxima near 2.93, 2.61, 2.34 and 1.9 eV. The luminescence spectra of CdWO4:Tb,Li at 10 K may be presented by the superposition of elementary matrix bands 2.07, 2.47 and 2.73 eV and narrow bands (lines) associated with f-f-transitions in Tb³⁺ ions. The nature of emission bands is discussed.