On the luminescence properties of CaSO4:Ce.
The luminescent properties of cerium doped calcium sulphate are studied: fluorescence and excitation spectra, optical absorption and thermoluminescence (TSL). It is known that, in rare earth doped CaSO4, only cerium induces a strong 400 degrees C TSL peak. In CaSO4:0.2%Ce samples synthesised under oxidising conditions, the recovery step of Ce3+ fluorescence is correlated with the 400 degrees C TSL peak readout, as mentioned by Nair er al. Our results indicate that an oxidation of Ce3+ ion does occur under X-irradiation (Ce3+ --> Ce4+), followed by a complete return to the trivalent state after thermal annealing at about 500 degrees C; our results confirm the hypothesis of Nair et al that Ce3+ ions are oxidised by ionising irradiation. So, a pure redox reaction seems the most probable for the 400 degrees C TSL peak of CaSO4:Ce. Moreover, the use of the 400 degrees C TSL peak for high temperature dosimetry applications is discussed.
Lapraz
D
D
Laboratoire de Physique Electronique des Solides (LPES), Centre de Recherches sur les Solides et leurs Applications (CRESA), EA 1174, Faculté des Sciences, Université de Nice-Sophia Antipolis, Nice, France. lapraz@unice.fr
Prevost
H
H
Iacconi
P
P
Guigues
C
C
Benabdesselam
M
M
Briand
D
D
D002133:Calcium Sulfate / Q000737:chemistry / Q000528:radiation effects*; D002563:Cerium / Q000737:chemistry; D008163:Luminescent Measurements; D055095:Optics and Photonics; D011854:Radiochemistry; D013053:Spectrophotometry; D013819:Thermoluminescent Dosimetry / Q000379:methods*
D002563:Cerium; D002133:Calcium Sulfate