Thermoluminescence in fluorapatite doped with Eu2O3 and PbO

Thermoluminescence (TL) of fluorapatite Ca5(PO4)3F doped with Eu2O3 has been investigated for UV and X ray irradiation. Two TL glow peaks for the Eu2O3 doped sample appeared in the temperature regions about (1) 353 to 380 K and (2) 508 to 510 K, when heated at rate of 20 K.min-1 after UV or X ray irradiation at room temperature. It has been found that the peak 2 (508 to 510 K) intensity of the samples doubly doped with Eu2O3 and PbO became strong compared with that doped with only Eu or Pb ions. From the TL spectra for the Ca5(PO4)3F doped activators, it is concluded that the TL of Eu2+ ions is sensitised by the existence of Pb2+ ions. On the other hand, the TL of Eu3+ ions is not intensified by addition of PbO. The TL emission may be due to the recombination reaction: Eu3+ + e R Eu2+ R Eu2+ + hv.Eu2+ + hole R Eu3+ R Eu3+ + hv. The 510 K TL peak may be also being suitable for use as a dosemeter. (author)