Dr Kabita Satapathy | Dayanand Sagar Institutions (original) (raw)

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Papers by Dr Kabita Satapathy

Mechanoluminescence and thermoluminescence of Tb in CaAl 2 O 4 prepared by a solution combustion ... more Mechanoluminescence and thermoluminescence of Tb in CaAl 2 O 4 prepared by a solution combustion method has been reported. Phase purity, formation of a phosphor and surface morphology were confirmed by XRD and SEM techniques. The resulting phosphors were characterized by photoluminescence (PL) to detect incorporation of the dopant. When a gamma-irradiated Tb-doped CaAl 2 O 4 crystal is impulsively deformed, two peaks appear in the ML intensity versus time curve, whereby the first ML peak is found in the deformation region and the second in the post deformation region of the crystals. The energy levels and hence trapping and detrapping mechanism of charge carriers can be explained using ML. The Tbdoped CaAl 2 O 4 phosphor can be used in the dosimetric applications for ionizing radiation. The TL characteristics of CaAl 2 O 4 may be useful for high radiation doses. Thermoluminescence (TL) materials have wide applications in the dosimetry of ionizing radiation, scintillators, X-ray laser materials, etc. The samples were irradiated using a 60 Co gamma-ray source at a dose of 0.930 kGy h À1 and the heating rate used for TL measurements was 5 C s À1. The samples show good TL peaks for 0.2 mol% (urea), 0.2 mol% (hydrazine) and 0.2 mol% (carbohydrazide) doping concentrations of Tb 3+ ions. We also report a more detailed theoretical understanding of the mechanism of TL and ML. All TL glow curves obey the secondorder kinetics with a single glow peak, which reveals that only one set of trapping parameters is set for a particular temperature. The TL sensitivity was found to depend upon the annealing temperature and Tb 3+ doping concentration. The prepared sample may be useful in TL dosimetry.

International Journal of Sciences: Basic and Applied Research, May 30, 2014

Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the p... more Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the process of combustion of corresponding metal nitrate-hydrazine mixtures, over a time of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were taken to investigate the luminescence centres. Two ML spectra were observed at around 455nm and 606nm. The ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. It is found that ML intensity of the phosphor depends on temperature and also the phosphor strongly depends on gamma ray dose given to it. The fading of the phosphor is quite low therefore it may be advantageously used for high temperature dosimetry applications.

International Journal of Sciences Basic and Applied Research, May 30, 2014

Europium doped monoclinic CaAl2O4 phosphors were obtained at low temperatures (500°C) by the proc... more Europium doped monoclinic CaAl2O4 phosphors were obtained at low temperatures (500°C) by the process of combustion of corresponding metal nitrate–hydrazine mixtures, over a time of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were taken to investigate the luminescence centres. Two ML spectra were observed at around 455nm and 606nm. The ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. It is found that ML intensity of the phosphor depends on temperature and also the phosphor strongly depends on gamma ray dose given to it. The fading of the phosphor is quite low therefore it may be advantageously used for high temperature dosimetry applications.

There are number of factors beside the physical state of the sample, the nature of excitation rad... more There are number of factors beside the physical state of the sample, the nature of excitation radiation and types of the impurity ions in a phosphor. Less attention has been paid to the effect of fuels on host preparation in its final performance. Tb(0.5mol%) doped MgAl 2O4 phosphors have been synthesised by solution combustion technique by using different fuel like carbohydrazide, hydrazine and urea and their photoluminescence (PL), thermoluminescence (TL) and mechanoluminescence (ML) properties have been studied. XRD result confirms formation of the phosphor. ML has been excited impulsively by dropping a load of mass 0.7 kg on to the phosphors from various heights. As the piston is dropped on to the sample, ML intensity initially increased with time attained an optimum value for a particular time then decreased again increases to a value than decreases and finally disappeared for all the samples. ML intensity increased with gamma doses given to the sample. PL emission spectrum sho...

Journal of Materials Science, 2012

Undoped and dysprosium (Dy)-doped BaB 4 O 7 phosphors have been synthesised by solid-state diffus... more Undoped and dysprosium (Dy)-doped BaB 4 O 7 phosphors have been synthesised by solid-state diffusion technique and its thermoluminescence (TL) and mechanoluminescence (ML) has been studied. A single peak at 162°C along with two shoulders around 242 and 294°C was observed in TL glow curve of undoped BaB 4 O 7 phosphors. TL intensity increased with increasing dopant concentration and broad band was observed for the sample having 0.5 mol% of dopant concentrations. For higher concentration of dopant, concentration quenching occurred. ML has been excited impulsively by dropping a piston of mass 0.6 kg on the phosphors with various impact velocities. As the piston was dropped on to the sample, ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. ML intensity varied with dopant concentration and it has been obtained optimum for the sample having 0.5 mol% of dopant. TL and ML intensity increased with gamma doses given to the sample. ML intensity increased almost linearly with the impact velocity of the piston dropped on to the sample, however, time corresponding to ML peak shifted towards shorter time value with increasing impact velocity of the piston dropped on to it. ML emission spectrum showed characteristic emission of Dy 3? ions. In order to study the influence of deformation on TL, TL was recorded after deforming the sample by dropping the load on to it. When the TL was recorded after deforming the sample, it is found that TL yield decreased markedly and it further decreased with increasing the height of the piston from which it was dropped. Results suggest that though the mode of excitation is different in these two phenomena but similar states are responsible for TL and ML.

Luminescence, 2014

Eu doped ZnAl2 O4 phosphors were synthesized by the solution combustion technique using carbohydr... more Eu doped ZnAl2 O4 phosphors were synthesized by the solution combustion technique using carbohydrazide as a fuel. Mechanoluminescence (ML) was excited impulsively by dropping a piston of 0.7 kg onto the phosphors. Two distinct peaks were observed in the ML glow curve of the γ-ray irradiated ZnAl2 O4 :Eu phosphors. Dependence of ML on various parameters as impact velocity of the piston dropped on to it, mass of the sample, gamma ray doses given to the sample and ML spectra have been studied. ML emission spectrum showed the characteristic emission of Eu(3+) ion in this system. ML is observed to be optimum for the sample having 0.2 mol% of Eu in the ZnAl2 O4 phosphor. XRD result confirms formation of the phosphors. SEM characterization shows its surface morphology. This novel phosphor may be a potential candidate for dosimetric use due to its linear dose response. Copyright © 2014 John Wiley & Sons, Ltd.

Journal of Chemistry, 2013

A reliable dosimetry is fundamental for quality assurance of the processes and irradiation produc... more A reliable dosimetry is fundamental for quality assurance of the processes and irradiation products. All dosimetric systems for high doses have some limitation with regard to their use. Dosimetric system should be easy to use, fast to measure, and of low cost. Good phosphor which shows high luminescence properties may fulfil the above criteria in some way. MgAl 2 O 4 : Dy phosphor has been prepared by solution combustion technique and confirmed with the help of XRD. ML has been excited impulsively by dropping a load of mass 0.7 kg onto the phosphors from various heights; two distinct ML peaks are observed for all the samples. It is observed that MgAl 2 O 4 : Dy phosphor shows linear response to gamma-ray dose and low fading which can be used for dosimetric purpose.

Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the p... more Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the process of combustion of corresponding metal nitrate-hydrazine mixtures, over a time of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were taken to investigate the luminescence centres. Two ML spectra were observed at around 455nm and 606nm. The ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. It is found that ML intensity of the phosphor depends on temperature and also the phosphor strongly depends on gamma ray dose given to it. The fading of the phosphor is quite low therefore it may be advantageously used for high temperature dosimetry applications.

Mechanoluminescence and thermoluminescence of Tb in CaAl 2 O 4 prepared by a solution combustion ... more Mechanoluminescence and thermoluminescence of Tb in CaAl 2 O 4 prepared by a solution combustion method has been reported. Phase purity, formation of a phosphor and surface morphology were confirmed by XRD and SEM techniques. The resulting phosphors were characterized by photoluminescence (PL) to detect incorporation of the dopant. When a gamma-irradiated Tb-doped CaAl 2 O 4 crystal is impulsively deformed, two peaks appear in the ML intensity versus time curve, whereby the first ML peak is found in the deformation region and the second in the post deformation region of the crystals. The energy levels and hence trapping and detrapping mechanism of charge carriers can be explained using ML. The Tbdoped CaAl 2 O 4 phosphor can be used in the dosimetric applications for ionizing radiation. The TL characteristics of CaAl 2 O 4 may be useful for high radiation doses. Thermoluminescence (TL) materials have wide applications in the dosimetry of ionizing radiation, scintillators, X-ray laser materials, etc. The samples were irradiated using a 60 Co gamma-ray source at a dose of 0.930 kGy h À1 and the heating rate used for TL measurements was 5 C s À1. The samples show good TL peaks for 0.2 mol% (urea), 0.2 mol% (hydrazine) and 0.2 mol% (carbohydrazide) doping concentrations of Tb 3+ ions. We also report a more detailed theoretical understanding of the mechanism of TL and ML. All TL glow curves obey the secondorder kinetics with a single glow peak, which reveals that only one set of trapping parameters is set for a particular temperature. The TL sensitivity was found to depend upon the annealing temperature and Tb 3+ doping concentration. The prepared sample may be useful in TL dosimetry.

International Journal of Sciences: Basic and Applied Research, May 30, 2014

Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the p... more Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the process of combustion of corresponding metal nitrate-hydrazine mixtures, over a time of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were taken to investigate the luminescence centres. Two ML spectra were observed at around 455nm and 606nm. The ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. It is found that ML intensity of the phosphor depends on temperature and also the phosphor strongly depends on gamma ray dose given to it. The fading of the phosphor is quite low therefore it may be advantageously used for high temperature dosimetry applications.

International Journal of Sciences Basic and Applied Research, May 30, 2014

Europium doped monoclinic CaAl2O4 phosphors were obtained at low temperatures (500°C) by the proc... more Europium doped monoclinic CaAl2O4 phosphors were obtained at low temperatures (500°C) by the process of combustion of corresponding metal nitrate–hydrazine mixtures, over a time of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were taken to investigate the luminescence centres. Two ML spectra were observed at around 455nm and 606nm. The ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. It is found that ML intensity of the phosphor depends on temperature and also the phosphor strongly depends on gamma ray dose given to it. The fading of the phosphor is quite low therefore it may be advantageously used for high temperature dosimetry applications.

There are number of factors beside the physical state of the sample, the nature of excitation rad... more There are number of factors beside the physical state of the sample, the nature of excitation radiation and types of the impurity ions in a phosphor. Less attention has been paid to the effect of fuels on host preparation in its final performance. Tb(0.5mol%) doped MgAl 2O4 phosphors have been synthesised by solution combustion technique by using different fuel like carbohydrazide, hydrazine and urea and their photoluminescence (PL), thermoluminescence (TL) and mechanoluminescence (ML) properties have been studied. XRD result confirms formation of the phosphor. ML has been excited impulsively by dropping a load of mass 0.7 kg on to the phosphors from various heights. As the piston is dropped on to the sample, ML intensity initially increased with time attained an optimum value for a particular time then decreased again increases to a value than decreases and finally disappeared for all the samples. ML intensity increased with gamma doses given to the sample. PL emission spectrum sho...

Journal of Materials Science, 2012

Undoped and dysprosium (Dy)-doped BaB 4 O 7 phosphors have been synthesised by solid-state diffus... more Undoped and dysprosium (Dy)-doped BaB 4 O 7 phosphors have been synthesised by solid-state diffusion technique and its thermoluminescence (TL) and mechanoluminescence (ML) has been studied. A single peak at 162°C along with two shoulders around 242 and 294°C was observed in TL glow curve of undoped BaB 4 O 7 phosphors. TL intensity increased with increasing dopant concentration and broad band was observed for the sample having 0.5 mol% of dopant concentrations. For higher concentration of dopant, concentration quenching occurred. ML has been excited impulsively by dropping a piston of mass 0.6 kg on the phosphors with various impact velocities. As the piston was dropped on to the sample, ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. ML intensity varied with dopant concentration and it has been obtained optimum for the sample having 0.5 mol% of dopant. TL and ML intensity increased with gamma doses given to the sample. ML intensity increased almost linearly with the impact velocity of the piston dropped on to the sample, however, time corresponding to ML peak shifted towards shorter time value with increasing impact velocity of the piston dropped on to it. ML emission spectrum showed characteristic emission of Dy 3? ions. In order to study the influence of deformation on TL, TL was recorded after deforming the sample by dropping the load on to it. When the TL was recorded after deforming the sample, it is found that TL yield decreased markedly and it further decreased with increasing the height of the piston from which it was dropped. Results suggest that though the mode of excitation is different in these two phenomena but similar states are responsible for TL and ML.

Luminescence, 2014

Eu doped ZnAl2 O4 phosphors were synthesized by the solution combustion technique using carbohydr... more Eu doped ZnAl2 O4 phosphors were synthesized by the solution combustion technique using carbohydrazide as a fuel. Mechanoluminescence (ML) was excited impulsively by dropping a piston of 0.7 kg onto the phosphors. Two distinct peaks were observed in the ML glow curve of the γ-ray irradiated ZnAl2 O4 :Eu phosphors. Dependence of ML on various parameters as impact velocity of the piston dropped on to it, mass of the sample, gamma ray doses given to the sample and ML spectra have been studied. ML emission spectrum showed the characteristic emission of Eu(3+) ion in this system. ML is observed to be optimum for the sample having 0.2 mol% of Eu in the ZnAl2 O4 phosphor. XRD result confirms formation of the phosphors. SEM characterization shows its surface morphology. This novel phosphor may be a potential candidate for dosimetric use due to its linear dose response. Copyright © 2014 John Wiley & Sons, Ltd.

Journal of Chemistry, 2013

A reliable dosimetry is fundamental for quality assurance of the processes and irradiation produc... more A reliable dosimetry is fundamental for quality assurance of the processes and irradiation products. All dosimetric systems for high doses have some limitation with regard to their use. Dosimetric system should be easy to use, fast to measure, and of low cost. Good phosphor which shows high luminescence properties may fulfil the above criteria in some way. MgAl 2 O 4 : Dy phosphor has been prepared by solution combustion technique and confirmed with the help of XRD. ML has been excited impulsively by dropping a load of mass 0.7 kg onto the phosphors from various heights; two distinct ML peaks are observed for all the samples. It is observed that MgAl 2 O 4 : Dy phosphor shows linear response to gamma-ray dose and low fading which can be used for dosimetric purpose.

Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the p... more Europium doped monoclinic CaAl 2 O 4 phosphors were obtained at low temperatures (500°C) by the process of combustion of corresponding metal nitrate-hydrazine mixtures, over a time of 5 min. The product was investigated by X-ray powder diffraction. Mechanoluminescence (ML) emission spectra were taken to investigate the luminescence centres. Two ML spectra were observed at around 455nm and 606nm. The ML intensity initially increased with time attained an optimum value for a particular time then decreased and finally disappeared. It is found that ML intensity of the phosphor depends on temperature and also the phosphor strongly depends on gamma ray dose given to it. The fading of the phosphor is quite low therefore it may be advantageously used for high temperature dosimetry applications.