Optically stimulated luminescence and spectral emission features of radioluminescence and thermoluminescence of natural kunzite:
- Alatishe, M A, Ogundare, F O, Folley, Damilola E, Chithambo, Makaiko L, Chikwembani, S
- Authors: Alatishe, M A , Ogundare, F O , Folley, Damilola E , Chithambo, Makaiko L , Chikwembani, S
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160478 , vital:40449 , https://doi.org/10.1016/j.radmeas.2020.106457
- Description: Features of luminescence optically stimulated from natural kunzite using 470 nm blue light are reported. Preparatory measurements of its X-ray excited radioluminescence and thermoluminescence show that the sample has two main bands centered at 360 nm and 600 nm. The optically stimulated luminescence discussed in this report was monitored in the UV region and is presumed to be the same 360 nm emission that appears in the radioluminescence and thermoluminescence spectra. The glow curve shows at least three peaks at 74, 202, 432 oC for heating at 1 oC and the third one is a composite of two. Only the first two peaks are deduced to contribute most of the optically stimulated luminescence.
- Full Text:
- Date Issued: 2020
- Authors: Alatishe, M A , Ogundare, F O , Folley, Damilola E , Chithambo, Makaiko L , Chikwembani, S
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160478 , vital:40449 , https://doi.org/10.1016/j.radmeas.2020.106457
- Description: Features of luminescence optically stimulated from natural kunzite using 470 nm blue light are reported. Preparatory measurements of its X-ray excited radioluminescence and thermoluminescence show that the sample has two main bands centered at 360 nm and 600 nm. The optically stimulated luminescence discussed in this report was monitored in the UV region and is presumed to be the same 360 nm emission that appears in the radioluminescence and thermoluminescence spectra. The glow curve shows at least three peaks at 74, 202, 432 oC for heating at 1 oC and the third one is a composite of two. Only the first two peaks are deduced to contribute most of the optically stimulated luminescence.
- Full Text:
- Date Issued: 2020
Thermoluminescence properties of potassium fluoride:
- Ogundare, F O, Folley, Damilola E, Chithambo, Makaiko L, Arise, T O
- Authors: Ogundare, F O , Folley, Damilola E , Chithambo, Makaiko L , Arise, T O
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160500 , vital:40451 , https://doi.org/10.1016/j.nimb.2020.09.009
- Description: This study is designed to examine the thermoluminescence characteristics of potassium fluoride for possible use as a thermoluminescence dosemeter. Thermoluminescence measurements were carried out at doses up to 20 Gy and heating rates between 0.2 and 4°C/s. The glow curve of the fluoride, readout at 1°Cs−1, exhibited two peaks at 130 and 250 °C. In addition, two shoulder peaks appeared at 70 and 200°C.
- Full Text:
- Date Issued: 2020
- Authors: Ogundare, F O , Folley, Damilola E , Chithambo, Makaiko L , Arise, T O
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160500 , vital:40451 , https://doi.org/10.1016/j.nimb.2020.09.009
- Description: This study is designed to examine the thermoluminescence characteristics of potassium fluoride for possible use as a thermoluminescence dosemeter. Thermoluminescence measurements were carried out at doses up to 20 Gy and heating rates between 0.2 and 4°C/s. The glow curve of the fluoride, readout at 1°Cs−1, exhibited two peaks at 130 and 250 °C. In addition, two shoulder peaks appeared at 70 and 200°C.
- Full Text:
- Date Issued: 2020
Relative features of the principal and secondary luminescence lifetimes in quartz
- Chithambo, Makaiko L, Ogundare, F O
- Authors: Chithambo, Makaiko L , Ogundare, F O
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125821 , vital:35820 , https://doi.10.1002/pssc.200673721
- Description: Quartz is a common natural mineral with properties that make it amenable for application in radiation dosimetry using luminescence methods [1]. The luminescence properties of quartz including its sensitivity and luminescence lifetimes undergo notable changes when the quartz is annealed, and in particular, near its phase inversion temperatures of 573 and 867 oC [2, 3]. The physical processes leading up to the emission of luminescence in quartz may be investigated using time-resolved optical stimulation. The aim of this method is to separate in time the stimulation and emission of luminescence to enable measurement of time-resolved luminescence spectra which may be resolved into associated lifetimes, defined in this sense as the delay between stimulation and emission of luminescence [4, 5]. A number of such studies show that annealing defines the detailed distribution of lifetimes with measurement temperature as well as the irradiation-dependent characteristics of the lifetimes [3, 6]. In particular, it was noted [3] that spectra measured at certain temperatures could be accurately resolved into more than one component, a scenario that pointed to the possibility of involvement of multiple luminescence centers in the emission of luminescence from quartz. The aim of this work is to build on the findings described, specifically to study the influence of measurement temperature and irradiation on the principal and subsidiary luminescence lifetimes in natural quartz.
- Full Text:
- Date Issued: 2017
- Authors: Chithambo, Makaiko L , Ogundare, F O
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125821 , vital:35820 , https://doi.10.1002/pssc.200673721
- Description: Quartz is a common natural mineral with properties that make it amenable for application in radiation dosimetry using luminescence methods [1]. The luminescence properties of quartz including its sensitivity and luminescence lifetimes undergo notable changes when the quartz is annealed, and in particular, near its phase inversion temperatures of 573 and 867 oC [2, 3]. The physical processes leading up to the emission of luminescence in quartz may be investigated using time-resolved optical stimulation. The aim of this method is to separate in time the stimulation and emission of luminescence to enable measurement of time-resolved luminescence spectra which may be resolved into associated lifetimes, defined in this sense as the delay between stimulation and emission of luminescence [4, 5]. A number of such studies show that annealing defines the detailed distribution of lifetimes with measurement temperature as well as the irradiation-dependent characteristics of the lifetimes [3, 6]. In particular, it was noted [3] that spectra measured at certain temperatures could be accurately resolved into more than one component, a scenario that pointed to the possibility of involvement of multiple luminescence centers in the emission of luminescence from quartz. The aim of this work is to build on the findings described, specifically to study the influence of measurement temperature and irradiation on the principal and subsidiary luminescence lifetimes in natural quartz.
- Full Text:
- Date Issued: 2017
Thermoluminescence of kunzite: a study of kinetic processes and dosimetry characteristics
- Ogundare, F O, Alatishe, M A, Chithambo, Makaiko L, Costin, G
- Authors: Ogundare, F O , Alatishe, M A , Chithambo, Makaiko L , Costin, G
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124701 , vital:35650 , https://doi.org/10.1016/j.nimb.2016.02.059
- Description: Since the use of natural minerals for dating and dose reconstruction using luminescence techniques is well-established and always of interest, we present thermoluminescence characteristics of kunzite, a gem variety of spodumene. The chemical composition of the sample was determined using an Electron Probe MicroAnalyzer.
- Full Text: false
- Date Issued: 2016
- Authors: Ogundare, F O , Alatishe, M A , Chithambo, Makaiko L , Costin, G
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124701 , vital:35650 , https://doi.org/10.1016/j.nimb.2016.02.059
- Description: Since the use of natural minerals for dating and dose reconstruction using luminescence techniques is well-established and always of interest, we present thermoluminescence characteristics of kunzite, a gem variety of spodumene. The chemical composition of the sample was determined using an Electron Probe MicroAnalyzer.
- Full Text: false
- Date Issued: 2016
Luminescence lifetime components in quartz: influence of irradiation and annealing
- Chithambo, Makaiko L, Ogundare, F O
- Authors: Chithambo, Makaiko L , Ogundare, F O
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6811 , http://hdl.handle.net/10962/d1004304
- Description: Pulsed optically stimulated luminescence measured from quartz under certain combinations of annealing and measurement temperature can be resolved into multiple lifetime components. We have studied the influence on these lifetime components of annealing temperature up to 900 °C, beta irradiation dose as high as 1700 Gy, and temperature of stimulation up to 200 °C. Although the time-resolved spectra from which the lifetimes are determined may be measured without heating between irradiation and measurement, a necessary protocol in steady-state optical stimulation applications, studies reported in this paper have been augmented with investigations on the effect of temperature and duration of preheating on the principal and secondary lifetimes. Luminescence spectra for measurements up to 200 Gy consist of a single lifetime but two components occur thereafter, both are independent of radiation dose. The principal lifetime of 35 μs is not affected by temperature of anneal whereas the secondary lifetime increases from 9 to 18 μs when the annealing temperature is changed from 600 to 900 °C. The dependence of both the principal and secondary luminescence lifetimes on measurement temperature can be explained by thermal quenching of the associated luminescence. However, the influence of irradiation, preheating, and annealing on the lifetimes can be explained with reference to an energy band scheme in which the primary mechanism in the processes leading up to luminescence emission is the change in concentration of holes at various luminescence centres caused by annealing.
- Full Text:
- Date Issued: 2009
- Authors: Chithambo, Makaiko L , Ogundare, F O
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6811 , http://hdl.handle.net/10962/d1004304
- Description: Pulsed optically stimulated luminescence measured from quartz under certain combinations of annealing and measurement temperature can be resolved into multiple lifetime components. We have studied the influence on these lifetime components of annealing temperature up to 900 °C, beta irradiation dose as high as 1700 Gy, and temperature of stimulation up to 200 °C. Although the time-resolved spectra from which the lifetimes are determined may be measured without heating between irradiation and measurement, a necessary protocol in steady-state optical stimulation applications, studies reported in this paper have been augmented with investigations on the effect of temperature and duration of preheating on the principal and secondary lifetimes. Luminescence spectra for measurements up to 200 Gy consist of a single lifetime but two components occur thereafter, both are independent of radiation dose. The principal lifetime of 35 μs is not affected by temperature of anneal whereas the secondary lifetime increases from 9 to 18 μs when the annealing temperature is changed from 600 to 900 °C. The dependence of both the principal and secondary luminescence lifetimes on measurement temperature can be explained by thermal quenching of the associated luminescence. However, the influence of irradiation, preheating, and annealing on the lifetimes can be explained with reference to an energy band scheme in which the primary mechanism in the processes leading up to luminescence emission is the change in concentration of holes at various luminescence centres caused by annealing.
- Full Text:
- Date Issued: 2009
Time-resolved luminescence of low sensitivity quartz from crystalline rocks
- Chithambo, Makaiko L, Preusser, F, Ramseyer, K, Ogundare, F O
- Authors: Chithambo, Makaiko L , Preusser, F , Ramseyer, K , Ogundare, F O
- Date: 2007
- Language: English
- Type: text , article
- Identifier: vital:6801 , http://hdl.handle.net/10962/d1004164 , https://doi.org/10.1016/j.radmeas.2006.07.005
- Description: preprint , Time-resolved luminescence spectra of low sensitivity natural quartz from crystalline rocks are presented. The luminescence was pulse-stimulated at width using 470 nm blue light from quartz separated from plutonic, metamorphic, volcanic and hydrothermal samples. Measurements were made at 20 °C. All samples show evidence of a short lifetime component less than long although in several cases too weak in intensity to be evaluated accurately. On the other hand, the value of the principal lifetime component varies considerably being about in metamorphic quartz, in plutonic quartz, and in one example of hydrothermal quartz. The results illustrate a new feature of luminescence from quartz for which lifetimes less than or greater than have never been reported at room temperature before. It is argued that the thermal provenance of the quartz and so the annealing it will have experienced influences the size of the observed lifetime. In particular, the results are explained in terms of a model consisting of three luminescence centers with the dominant lifetime linked to preferential recombination at one center depending on the thermal history of the sample and hence the hole concentration of the center.
- Full Text:
- Date Issued: 2007
- Authors: Chithambo, Makaiko L , Preusser, F , Ramseyer, K , Ogundare, F O
- Date: 2007
- Language: English
- Type: text , article
- Identifier: vital:6801 , http://hdl.handle.net/10962/d1004164 , https://doi.org/10.1016/j.radmeas.2006.07.005
- Description: preprint , Time-resolved luminescence spectra of low sensitivity natural quartz from crystalline rocks are presented. The luminescence was pulse-stimulated at width using 470 nm blue light from quartz separated from plutonic, metamorphic, volcanic and hydrothermal samples. Measurements were made at 20 °C. All samples show evidence of a short lifetime component less than long although in several cases too weak in intensity to be evaluated accurately. On the other hand, the value of the principal lifetime component varies considerably being about in metamorphic quartz, in plutonic quartz, and in one example of hydrothermal quartz. The results illustrate a new feature of luminescence from quartz for which lifetimes less than or greater than have never been reported at room temperature before. It is argued that the thermal provenance of the quartz and so the annealing it will have experienced influences the size of the observed lifetime. In particular, the results are explained in terms of a model consisting of three luminescence centers with the dominant lifetime linked to preferential recombination at one center depending on the thermal history of the sample and hence the hole concentration of the center.
- Full Text:
- Date Issued: 2007
Accuracy of the activation energy calculated from a thermoluminescence glow‐peak using a method that uses three points on the peak
- Ogundare, F O, Chithambo, Makaiko L
- Authors: Ogundare, F O , Chithambo, Makaiko L
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123016 , vital:35397 , https://doi:10.1002/pssc.200521077
- Description: The utility of thermoluminescence (TL) in detecting changes in defect concentration in insulators is well established [1–3]. The underlying premise leading to the emission of TL is that exposure of a material to ionizing radiation causes a redistribution of charge in defect centres within the material. When the material is heated at a controlled linear rate, the thermoluminescence is emitted as a temperature-dependent set of peaks collectively known as a glow-curve. The shape and intensity of each of the glow-peaks may be characterized by a set of parameters consisting of the activation energy E, the frequency factors, the number of electrons n0 trapped in defect centres at the start of the heating, and the order of kinetics b. The order of kinetics b is an indication of the retrapping probability i.e. the probability that a free electron from the conduction band will be retrapped rather than recombine with a hole at a recombination centre to produce thermoluminescence. Retrapping of electrons reduces the TL intensity at any particular temperature during the heating process. The physical mechanisms of TL associated with a given glow curve are unique and may be characterized by analysis of the glow-curve for the said kinetic parameters.
- Full Text:
- Date Issued: 2006
- Authors: Ogundare, F O , Chithambo, Makaiko L
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123016 , vital:35397 , https://doi:10.1002/pssc.200521077
- Description: The utility of thermoluminescence (TL) in detecting changes in defect concentration in insulators is well established [1–3]. The underlying premise leading to the emission of TL is that exposure of a material to ionizing radiation causes a redistribution of charge in defect centres within the material. When the material is heated at a controlled linear rate, the thermoluminescence is emitted as a temperature-dependent set of peaks collectively known as a glow-curve. The shape and intensity of each of the glow-peaks may be characterized by a set of parameters consisting of the activation energy E, the frequency factors, the number of electrons n0 trapped in defect centres at the start of the heating, and the order of kinetics b. The order of kinetics b is an indication of the retrapping probability i.e. the probability that a free electron from the conduction band will be retrapped rather than recombine with a hole at a recombination centre to produce thermoluminescence. Retrapping of electrons reduces the TL intensity at any particular temperature during the heating process. The physical mechanisms of TL associated with a given glow curve are unique and may be characterized by analysis of the glow-curve for the said kinetic parameters.
- Full Text:
- Date Issued: 2006
Anomalous behaviour of thermoluminescence from quartz: a case of glow peaks from a Nigerian quartz
- Ogundare, F O, Chithambo, Makaiko L, Oniya, E O
- Authors: Ogundare, F O , Chithambo, Makaiko L , Oniya, E O
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6796 , http://hdl.handle.net/10962/d1003922
- Description: Anomalous behaviour displayed by a thermoluminescence (TL) glow peak as radiation dose increases in a Nigerian quartz is presented. The glow curves of the phosphor have four clear glow peaks. The peak temperatures of the first three glow peaks were found to be constant with change in radiation dose at 82, 148 and 200ºC for the sample readout at a heating rate of 1ºCs[superscript (-1)]. The peak temperature of the fourth peak, which is at around 320ºC for a sample irradiated to a dose of 63 Gy and heated at 1ºCs[superscript (-1)], displays anomalous behaviour with increase in dose relative to the first three peaks. The temperature at which this peak occurs increases with dose to about 335ºC for 177 Gy and then decreases thereafter as dose is further increased. The change is explained on the assumption that the peak may be complex consisting of several overlapping first-order glow peaks each with different TL behaviour.
- Full Text:
- Date Issued: 2006
- Authors: Ogundare, F O , Chithambo, Makaiko L , Oniya, E O
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6796 , http://hdl.handle.net/10962/d1003922
- Description: Anomalous behaviour displayed by a thermoluminescence (TL) glow peak as radiation dose increases in a Nigerian quartz is presented. The glow curves of the phosphor have four clear glow peaks. The peak temperatures of the first three glow peaks were found to be constant with change in radiation dose at 82, 148 and 200ºC for the sample readout at a heating rate of 1ºCs[superscript (-1)]. The peak temperature of the fourth peak, which is at around 320ºC for a sample irradiated to a dose of 63 Gy and heated at 1ºCs[superscript (-1)], displays anomalous behaviour with increase in dose relative to the first three peaks. The temperature at which this peak occurs increases with dose to about 335ºC for 177 Gy and then decreases thereafter as dose is further increased. The change is explained on the assumption that the peak may be complex consisting of several overlapping first-order glow peaks each with different TL behaviour.
- Full Text:
- Date Issued: 2006
Evaluation of kinetic parameters of traps in thermoluminescence phosphors
- Ogundare, F O, Balogun, F A, Hussain, L
- Authors: Ogundare, F O , Balogun, F A , Hussain, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6798 , http://hdl.handle.net/10962/d1003924 , http://dx.doi.org/10.1016/j.radmeas.2006.06.014
- Description: A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria.
- Full Text:
- Date Issued: 2006
- Authors: Ogundare, F O , Balogun, F A , Hussain, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6798 , http://hdl.handle.net/10962/d1003924 , http://dx.doi.org/10.1016/j.radmeas.2006.06.014
- Description: A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria.
- Full Text:
- Date Issued: 2006
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