Browsing by Author "Oniya, E. O."

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    Simulation of an anomalous behavior of thermoluminescence glow peak of quartz from Nigeria
    (Ankara : Ankara Üniversitesi, 2017) Oniya, E. O.; Olubi, O. E.; Fen Fakültesi
    Mechanism of the experimentally observed anomalous shift of a thermoluminescence (TL) glow peak that varied with irradiation dose is yet to be fully established. A theory that the anomalous peak must have contained more than one first order composite peaks each with different TL dose characteristics has been one major explanation proposed to explain this observation. This work was undertaken to simulate the anomalous glow peak by using a modified version of a previously proposed model and numerically solving sets of simultaneous differential equations governing the stages of TL phenomena (excitation, relaxation and heating). In the modified model, two additional electron trapping centers were incorporated in order to simulate accurately this glow curve. Computerized glow curve deconvolution (CGCD) analyses was carried out on the simulated glow peak in attempt to retrieve back the electron trapping center energies and to identify their respective peak positions. The outcome of this confirmed the peak to be possibly composite in nature comprising of three overlapping glow peaks at 288, 300 and 317oC with respective energy gaps of 1.70, 1.73 and 1.75eV. It is therefore further substantiated that this kind of temperature shift of peak with dose resulting from composite glow peaks is possible.
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    Variations in Luminescence Sensitivity of Various Quartz Samples from Southwestern Nigeria
    (Ankara : Ankara Üniversitesi, 2018) Oniya, E. O.; Fen Fakültesi
    This research was undertaken to investigate the sensitivity of Thermoluminescence (TL), Optically Stimulated Luminescence (OSL) and Infra-Red Stimulation Luminescence (IRSL) of twelve (12) quartz samples from different locations in the Southwestern part of Nigeria. This was done with a motive to survey the provenance suitability of each one of them for luminescence dating. All the luminescence measurements on the 12 quartz samples were carried out using a Risø TL/OSL read (model TL/OSL-DA-15). Each of the samples displayed different range of luminescence responses to the same test dose. The sensitivity of the TL and OSL did not follow identical pattern for all the samples but that of LMOSL and CW-OSL demonstrated nearly identical pattern. Effect of feldspar inclusion seemed passive in TL but highly active in OSL most especially fast component. The two samples that exhibited highest OSL signal failed to pass feldspar inclusion test. The significance of feldspar inclusion in SAR protocols was stressed. Further studies on the samples at varying test doses may improve the understanding of the behaviour of these samples.