52 research outputs found

    Reply to Comments on Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7:Cu,Ag,P in TSL measurements

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    We appreciate the opportunity to respond to comments regarding the paper published by Ege et al (2007 Effect of heating rate on kinetic parameters of beta-irradiated Li2B4O7: Cu, Ag, P in TSL measurements Meas. Sci. Technol. 18 889). We would like to thank the authors for taking the time to tell us about their opinion, but unfortunately we do not agree with them completely. In the article presented by Kumar and Chourasiya some comment is advanced to the analysis of the glow curves measured with different heating rates, presented in our recent study. According to our study, the area under the glow curve decreases with increasing heating rate in TL-temperature plots due to the quenching effects. Contrary to this, Kumar and Chourasiya suggest that this decrease is due to the normalization process. Here we hope to clarify any confusion regarding our published study

    Data sharing reveals complexity in the westward spread of domestic animals across Neolithic Turkey

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    This study presents the results of a major data integration project bringing together primary archaeozoological data for over 200,000 faunal specimens excavated from seventeen sites in Turkey spanning the Epipaleolithic through Chalcolithic periods, c. 18,000-4,000 cal BC, in order to document the initial westward spread of domestic livestock across Neolithic central and western Turkey. From these shared datasets we demonstrate that the westward expansion of Neolithic subsistence technologies combined multiple routes and pulses but did not involve a set 'package' comprising all four livestock species including sheep, goat, cattle and pig. Instead, Neolithic animal economies in the study regions are shown to be more diverse than deduced previously using quantitatively more limited datasets. Moreover, during the transition to agro-pastoral economies interactions between domestic stock and local wild fauna continued. Through publication of datasets with Open Context (opencontext.org), this project emphasizes the benefits of data sharing and web-based dissemination of large primary data sets for exploring major questions in archaeology (Alternative Language Abstract S1)

    GEOCHRONOMETRIA

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    Ceramic findings collected from YeAYilova Hoyuk located in Izmir were dated using the thermoluminescence dating technique. The area is of significant archaeological importance since it is the first prehistoric settlement in Izmir. Recent archeological observations suggest that human occupation of the region took place about 8500 years ago comparing to previously determined dates of 5000 years. Three samples collected from the same archaeological layer (Neolithic period) in YeAYilova Hoyuk were dated using the thermoluminescence method. Archaeological doses (AD) were obtained by single aliquot regenerative dose method (SAR) for thermoluminescence (TL) using coarse grain quartz minerals extracted from samples. Thick and thin Al2O3:C thermoluminescence dosimeters (TLD) were used to determine the annual dose rate. The archaeological doses were found to vary from 25.91 +/- 0.78 to 26.82 +/- 0.68 Gy, and the annual doses were found to be between 3.34 +/- 0.24 and 3.47 +/- 0.24 mGy/a. The ages obtained for the samples were determined to be 6000 +/- 830 BC, 5740 +/- 670 BC and 5460 +/- 740 years for samples ND1, ND2 and ND3, respectively, which supports the prediction of archeologist that the sampling layer dates from the Neolithic period

    APPLIED RADIATION AND ISOTOPES

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    In this study, structural and luminescence properties of magnesium borate of the form MgB4O7 doped with Tm and Na were investigated by X-ray diffraction (XRD), Raman spectroscopy and cathodoluminescence (CL). The morphologies of the synthetised compounds exhibit clustered granules and road-like materials. As doping trivalent ions into a host with divalent cations requires charge compensation, this effect is discussed. The CL spectra of undoped MgB4O7 shows a broad band emission centred around 350 nm which is postulated to be produced by self-trapped excitons and some other defects. From the CL emission spectrum, main emission bands centred at 360, 455, 475 nm due to the respective transitions of D-1(2)-> H-3(6),D-1(2)-> F-3(4) and (1)G(4)-> H-3(6) suggest the presence of Tm3+ ion in MgB4O7 lattice site. CL mechanism was proposed to explain the observed phenomena which are valuable in possibility of the developing new luminescent materials for different applications. In addition, the experimental Raman spectrum of doped and undoped MgB4O7 were reported and discussed. (C) 2015 Elsevier Ltd. All rights reserved

    JOURNAL OF LUMINESCENCE

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    The physical characterization and phosphor emission spectra are presented for CaSO4 doped with Tm and Cu. All spectral wavelengths are related to electronic transitions of Tm3+ ions. The powder X-ray diffraction pattern showed that the compound exhibits orthorhombic structure and all reflections were indexed without any other secondary impurity phases. Chemical and structural properties of the samples have been characterized by means of Raman spectroscopy and environmental scanning electron microscope (ESEM) with an attached X-ray energy dispersive system (EDS). Group frequencies concept is essential point to the interpretation of the bands due to the main SO4 vibrational units and these displayed main characteristic intensive Raman bands including typical strong intensity at 1016 cm(-1) that corresponds to v(1)SO(4) vibrational mode. From the spatially-resolved cathodoluminescence (CL) spectrum, main emission bands of Tm3+ centered at 346, 362, and 452 nm, due to the respective transitions of P-3(0) -> H-3(4), D-1(2) -> H-3(6), D-1(2) -> F-3(4) were clearly identified. The study is novel as no such CL-ESEM data are available for this doped compound. (C) 2015 Elsevier B.V. All rights reserved

    Determination of thermoluminescence kinetic parameters of Li2B4O7 : Cu, Ag, P

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    WOS: 000251921900003The kinetic parameters of a newly prepared tissue-equivalent, highly sensitive thermoluminescent detector, Li2B4O7: Cu, Ag, P of sintered pellets have been calculated. Thermoluminescence (TL) glow curves of Li2B4O7: Cu, Ag, P samples after beta-irradiation showed peaks at about 384 and 446 K with a heating rate of I K s(-1). The kinetic parameters, namely activation energy (E) and frequency factor (s) associated with the main glow peak (446 K) of Li2B4O7: Cu, Ag, P have been determined using isothermal decay (ID) and peak shape (PS) methods. The activation energies obtained by ID and PS methods are calculated to be 1.12 and 1.13eV (mean), respectively. The frequency factors obtained by both methods are 7.61 x 1011 and 3.53 x 1011 s(-1) (mean), respectively. Results obtained using both methods are compared and discussed. (c) 2007 Elsevier Ltd. All rights reserved
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