M. Bohm et al., Electron traps in the scintillator material PbWO4 and their correlation tothermally stimulated luminescence, RADIAT EFF, 150(1-4), 1999, pp. 21-27
Various efforts to improve radiation hardness and scintillation properties
of lead tungstate with respect to its application in high energy calorimete
rs by doping with suitable ions like Nb, La, Gd or Lu have been checked for
their success mainly by studying optical absorption and thermally stimulat
ed luminescence (TSL) after irradiation at room temperature, in a few cases
at liquid nitrogen temperature. Very shallow traps, which contribute to fa
st scintillation processes, are not stabilized under such conditions. Exten
ding the temperature range for irradiation as well as for experimental stud
ies down to liquid helium temperature, we found new TSL glow peaks and esta
blished a correlation to electrons captured by anionic WO4 complexes. Their
electron spin resonance (ESR) data together with other experimental result
s like temperature dependence of photoconductivity give distinct hints with
respect to the energy level scheme of PbWO4.