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    Room and Low Temperature Luminescence Properties of CaSO4:Dy,Tm Codoped with Li
    (ELSEVIER SCIENCE BV, 2009) Can, N.; Karali, T.; Wang, Y.; Townsend, P. D.; Prokic, M.; Canimoglu, A.; Boulon, G; Dujardin, C; Jurdyc, AM
    Rare earths, especially Dy or Tm doped CaSO4 phosphors are actively studied. They have high sensitivity, a large dynamic range, thermal stability and ease of preparation. Nevertheless, they can be enhanced by inclusion of lithium and this study reports some effects of lithium co-dopant on the TL and radioluminescence (RL) emissions of two TL phosphors. Addition of Li as a co-dopant ion was made either during chemical preparation of the phosphors, or as a binder component mixed with the basic phosphors matrix during the process of pressing and sintering the TLD pellets.
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    Study of luminescence of Mn-doped CaB4O7 prepared by wet chemical method
    (ELSEVIER SCIENCE SA, 2016) Oguz, K. F.; Ekdal, E.; Aslani, M. A. A.; Canimoglu, A.; Garcia Guinea, J.; Can, N.; Karali, T.
    In this study, manganese (Mn) doped Calcium Tetraborate (CaB4O7) samples were prepared by the wet chemical method. Under beta irradiated, CaB4O7:Mn showed thermally stimulated luminescence (TSL) glow peaks at approximately 85 degrees C and 220 degrees C with a heating rate of 5 degrees C/s. Peak shape (PS) and various heating rates (VHR) methods were applied for determining the trap parameters such as order of kinetic (b), activation energy (E) and frequency factor (s). The results indicate that the main dosimetric peak of CaB4O7:Mn follows the second-order kinetic model. The thermal fading ratio of the material is around 15% at the end of one month period of storage. The results of the TL studies carried out on the CaB4O7:Mn dosimeter revealed that it has high sensitivity, which makes it very valuable in various dosimetric applications like space, medical, personal dosimetry and dating. Radioluminescence (RL) of CaB4O7:Mn was also studied. It is shown that the RL spectrum contains a wide band centered at 530 nm assigned to Mn2+ ion emission. A broad band emission feature peaked at 350 nm assigned to the non-bridging oxygen hole center (NBOHC) is also discussed and a model is proposed to explain this broad band feature. (C) 2016 Elsevier B.V. All rights reserved.
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    Thermoluminescence studies of Nd doped Bi4Ge3O12 crystals irradiated by UV and beta sources
    (PERGAMON-ELSEVIER SCIENCE LTD, 2016) Karabulut, Y.; Canimoglu, A.; Ekdal, E.; Ayvacikli, M.; Can, N.; Karali, T.
    Thermoluminescence (TL) glow curves of pure and rare earth doped bismuth germanate (BGO) were investigated under UV and beta radiation. The glow curves of pure BGO crystal present different patterns for both kinds of radiation. The TL glow curves of BGO crystals doped with Nd ions are similar to that of pure BGO under UV radiation. The kinetic parameters, kinetic order (b), activation energy (E) and frequency factor (s) of the TL glow curves of pure BGO crystal have been determined by peak shape method. Activation energies of 3 peaks obtained by PS were found to be 1.81, 1.15 and 1.78, respectively. (C) 2016 Elsevier Ltd. All rights reserved.
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    Visible to infrared low temperature photoluminescence of rare earth doped bismuth germanate crystals
    (PERGAMON-ELSEVIER SCIENCE LTD, 2016) Canimoglu, A.; Ayvacikli, M.; Karabulut, Y.; Karali, T.; Can, N.
    In this paper, the influence of a series of rare earth (Eu, Tm, Nd) and Cr ion doping on the optical properties of BGO was investigated by means of photoluminescence (PL) from visible to IR region in the 10-300 K temperature range using different types of detectors, namely, photomultiplier tube (PMT), InGaAs (IGA), and Si. Several samples were investigated having dopants concentrations of 03 wt%Nd, 0.4 wt%Tm, 0.06 wt% Cr and 3 ppm Eu. The PL spectra of the samples showed different luminescence behaviour which is assigned to the 4f intra shell transition from rare earth ions. The temperature dependence of the PL from rare earth doped BGO crystals is also examined. (C) 2016 Elsevier Ltd. All rights reserved.