Effect of annealing on the luminescene property of PbWO₄ crystals grown by the Czochralski method

PWO Crystals grown by the Czochralski method were annealed under different conditions. The transmittance of PWO crystal was decreased when it was annealed in an oxygen-rich environment; whereas it was increased when the crystal was annealed in vacuum. A mechanism on the transmittance change was proposed. The main peaks of X-ray exited emission spectra showed that both as-grown and vacuum-annealed crystals fit into blue light region with the latter one showing higher intensity. The oxygen-rich annealed crystal shifted to longer wavelength of green light region at lower intensity. The faster components in the light yield of crystals annealed in vacuum were higher correspondence to its higher intensity of the blue light.