Study of oriented CdWO4 scintillating crystals using synchrotron radiation

Absorption, reflection, excitation and polarization spectra of CdWO4 crysta ls have been studied in the region 3.5-30 eV in order to distinguish betwee n the excitonic and electron-hole processes in the vicinity of the band-gap . An energy gap of 5 eV has been determined from the Urbach tail study at 1 00-300 K. Excitonic processes have been shown to dominate at lower energies . A new fast emission band peaking at 3.6 eV has been found under pulsed el ectron (300 keV, 3 ns) excitation and presumably ascribed to the metastable oxyanionic exciton. (C) 2001 Elsevier Science Ltd. All rights reserved.