Thermoluminescence Mechanism on SiO2 Phosphor

The various studies of dose-assessment for natural radiation have been done in the high background radiation areas (HBRA) around the world. The radiations from cosmic rays have been measured using with radiation detectors such as NaI scintillation survey meters, electronic pocket dosimeters and thermoluminescence dosimeters (TLD). In the occasion without these instruments, natural SiO2 crystals collected in the HBRA is expected to be usable for the dosimetry of radiations from underground. The TL dosimetry using the natural SiO2 crystals have already been performed in high-dose areas due to a nuclear accident like JCO accident happened on September 1999. The TL from a natural SiO2 crystal gives historical information in relation with the collected layers, not only the total dose. Thus, this method can make available discussing the origin of high-dose in HBRA. However, the TL mechanism has not yet been well explained; it is necessary to make TL mechanism to be clear in order to establish more quantitative dosimetry. Then, in this study, TL spectra was examined for synthesized SiO2 phosphor doped with Al3+ and/or Eu3+, that are reported as the source of blue and red TL emissions, respectively and compared with that for natural SiO2 crystals. Furthermore, it will be discussed how to establish the quantitative TL dosimetry using natural SiO2 crystals.6th Internationl Conference on High Levels of Natural Radiation and Radon Area