Ultraviolet-induced thermoluminescence and phosphorescence in Mg2SiO4:Tb.
Among the common TLD materials studied (Mg2SiO4:Tb, Al2O3:Si, Ti, CaSO4:Tm, CaSO4:Dy, Li2B4O7:Mn and LiF TLD-100), Mg2SiO4:Tb was found to have the highest intrinsic TL sensitivity to UV radiation (wavelength 253.7 nm). The TL response of the dosimetric peak (approximately 200 degrees C) of virgin Mg2SiO4:Tb was studied as a function of UV exposure in the range 10--10(4) J m-2. The UV-induced TL was not affected by room-light and no appreciable fading was observed up to 20 days after irradiation indicating that this is a promising TL phosphor for UV dosimetry. The UV sensitivity was found to increase with increasing preliminary gamma exposure above 10(-2)Ckg-1 (after a post-irradiation anneal at 300 degrees C for 1 h). The degree of sensitisation was found proportional to the intensity of the residual TL peak at 450 degrees C. A study of the TL response of the sensitised sample as a function of UV test exposure has demonstrated the transfer of charge carriers from the deep traps to the dosimetry traps. Both virgin and gamma-exposed Mg2SiO4:Tb were found to exhigit phosphorescence decay at room temperature after UV stimulation. The intensity of the UV stimulated phosphorescence was found to increase with the gamma exposure above 10(-2) C kg-1.
D000537:Aluminum Oxide; D002118:Calcium; D005720:Gamma Rays; D008274:Magnesium; D011829:Radiation Dosage; D012822:Silicon Dioxide; D013431:Sulfates; D013725:Terbium; D013819:Thermoluminescent Dosimetry; D014466:Ultraviolet Rays
D013431:Sulfates; D013725:Terbium; D012822:Silicon Dioxide; D008274:Magnesium; D000537:Aluminum Oxide; D002118:Calcium