Through the study of the thermoluminescence(TL) of BaFClxBr1-x: Sm(0<x<1) system, it is found that former assignment of the glow peaks of BaFX(X = Cl, Br) is plausible. Through detailed study by several methods ...Through the study of the thermoluminescence(TL) of BaFClxBr1-x: Sm(0<x<1) system, it is found that former assignment of the glow peaks of BaFX(X = Cl, Br) is plausible. Through detailed study by several methods and techniques, a correct assignment is given in this paper, i.e. the first, second, and third glow peaks of BaFClxBr1-xSm are assigned to F(F-), F(Cl-), F(Br-) centers respectively, and the first andsecond glow peaks of BaFX are assigned to F(F-) and F(X-) centers respectively. This results are confirmed by theoretical consideration. Possible reasons for former plausible assignment are also pointed out here.展开更多
The essential objective of radiation dosimetry is to develop suitable sensitive materials for different measurements in radiation fields. Our exploration is to find potentially suitable high gamma radiation dosimeters...The essential objective of radiation dosimetry is to develop suitable sensitive materials for different measurements in radiation fields. Our exploration is to find potentially suitable high gamma radiation dosimeters in the range from 0.5E4 to 1.5E4 Gy. Gamma rays source (<sup>60</sup>Co, 136 Gy/min) has been used. Many compound semiconductor materials were prepared and investigated. Thermoluminescence (TL) glow curve was analyzed into its component by analytical segregation program using computerized glow curve deconvolution (CGCD). Three zero dose readings for non-irradiated powders of the materials have been taken as lower limit of detection. The results indicated that some of the tested materials have exhibited TL linearly with respect to dose. In addition, dose response of these materials was found to be useful for high radiation dosimetry. Glow curve structures exhibited several peaks corresponding to the various energies of the emptied traps. Variation in the standard deviation for reusability cycles has been ten readout. The fading at ambient temperature was studied up to 60 days which reached a relative stability (~1.5% for all), 10 days after irradiation. A typical glow curve of CoPa which irradiated with 1.5E4 Gy was analyzed. Characterizations of tested materials indicated that crystals of ZnLa:Li, ZnLa:Cd, and ZnLa:Cr have stable and increasing thermoluminescent responses with high gamma radiation dose range. Special glow peaks can be used as estimators for absorbed doses as well as re-estimation for time elapsed exposures.展开更多
Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food.Because of the rapid commercialization of irradiated foods throughout the...Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food.Because of the rapid commercialization of irradiated foods throughout the world,compliance of different regulations relating to use of technology in different countries and demand of consum- ers for clear labelling of irradiated foods,there is need for the development of analytical methods to detect radiation treatment of food.Among several methods studied so far,thermoluminescence (TL) is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles.In this study,the irradiated and unirradiated wheat and rice samples were analyzed using the TL method.The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture (NIFA),Peshawar.The mineral contaminants were isolated by jet water,ultrasonic treatment,and density gradient.TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50—500℃using a TL reader.Generally,the glow curves for irradiated samples showed much higher TL intensities (TL_1) than the unirradiated samples.The results were normalized by re-irradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves (TL_2).The ratio of the area of first glow curve to that of second glow curve (TL_1/TL_2) was calcu- lated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples.Finally,the shapes of the glow curves for irradiated and unirradiated samples were also analyzed.On the ba- sis of these results (comparison of TL-intensities,TL_1/TL_2 ratios and shapes of the glow curves),all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.展开更多
Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results du...Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.展开更多
文摘Through the study of the thermoluminescence(TL) of BaFClxBr1-x: Sm(0<x<1) system, it is found that former assignment of the glow peaks of BaFX(X = Cl, Br) is plausible. Through detailed study by several methods and techniques, a correct assignment is given in this paper, i.e. the first, second, and third glow peaks of BaFClxBr1-xSm are assigned to F(F-), F(Cl-), F(Br-) centers respectively, and the first andsecond glow peaks of BaFX are assigned to F(F-) and F(X-) centers respectively. This results are confirmed by theoretical consideration. Possible reasons for former plausible assignment are also pointed out here.
文摘The essential objective of radiation dosimetry is to develop suitable sensitive materials for different measurements in radiation fields. Our exploration is to find potentially suitable high gamma radiation dosimeters in the range from 0.5E4 to 1.5E4 Gy. Gamma rays source (<sup>60</sup>Co, 136 Gy/min) has been used. Many compound semiconductor materials were prepared and investigated. Thermoluminescence (TL) glow curve was analyzed into its component by analytical segregation program using computerized glow curve deconvolution (CGCD). Three zero dose readings for non-irradiated powders of the materials have been taken as lower limit of detection. The results indicated that some of the tested materials have exhibited TL linearly with respect to dose. In addition, dose response of these materials was found to be useful for high radiation dosimetry. Glow curve structures exhibited several peaks corresponding to the various energies of the emptied traps. Variation in the standard deviation for reusability cycles has been ten readout. The fading at ambient temperature was studied up to 60 days which reached a relative stability (~1.5% for all), 10 days after irradiation. A typical glow curve of CoPa which irradiated with 1.5E4 Gy was analyzed. Characterizations of tested materials indicated that crystals of ZnLa:Li, ZnLa:Cd, and ZnLa:Cr have stable and increasing thermoluminescent responses with high gamma radiation dose range. Special glow peaks can be used as estimators for absorbed doses as well as re-estimation for time elapsed exposures.
文摘Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food.Because of the rapid commercialization of irradiated foods throughout the world,compliance of different regulations relating to use of technology in different countries and demand of consum- ers for clear labelling of irradiated foods,there is need for the development of analytical methods to detect radiation treatment of food.Among several methods studied so far,thermoluminescence (TL) is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles.In this study,the irradiated and unirradiated wheat and rice samples were analyzed using the TL method.The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture (NIFA),Peshawar.The mineral contaminants were isolated by jet water,ultrasonic treatment,and density gradient.TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50—500℃using a TL reader.Generally,the glow curves for irradiated samples showed much higher TL intensities (TL_1) than the unirradiated samples.The results were normalized by re-irradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves (TL_2).The ratio of the area of first glow curve to that of second glow curve (TL_1/TL_2) was calcu- lated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples.Finally,the shapes of the glow curves for irradiated and unirradiated samples were also analyzed.On the ba- sis of these results (comparison of TL-intensities,TL_1/TL_2 ratios and shapes of the glow curves),all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.
文摘Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.
