The electromagnetic calorimeter of PANDA at the FAIR facility will rely on an operation of lead tungstate (PWO) scintillation crystals at temperatures near -25 deg.C to provide sufficient resolution for photons in the energy range from 8 GeV down to 10 MeV. Radiation hardness of PWO crystals was studied at the IHEP (Protvino) irradiation facility in the temperature range from room temperature down to -25 deg.C. These studies have indicated a significantly different behaviour in the time evolution of the damaging processes well below room temperature. Different signal loss levels at the same dose rate, but at different temperatures were observed. The effect of a deep suppression of the crystal recovery process at temperatures below 0 deg.C has been seen.
@article{arxiv.physics/0703199,
title = {First study of radiation hardness of lead tungstate crystals at low temperatures},
author = {P. A. Semenov and A. V. Uzunian and A. M. Davidenko and A. A. Derevschikov and Y. M. Goncharenko and V. A. Kachanov and V. Y. Khodyrev and A. P. Meschanin and N. G. Minaev and V. V. Mochalov and Y. M. Melnick and A. V. Ryazantsev and A. N. Vasiliev and S. F. Burachas and M. S. Ippolitov and V. Manko and A. A. Vasiliev and A. V. Mochalov and R. Novotny and G. Tamulaitis},
journal= {arXiv preprint arXiv:physics/0703199},
year = {2008}
}