Browsing by Author "Prokic M."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Kinetic characterization of MgB4O7: Dy,Na thermoluminescent phosphor
    (Institute of Physics Publishing, 2006) Karsu E.C.; Gökçe M.; Ege A.; Karali T.; Can N.; Prokic M.
    Dosimeters of MgB4O7 doped with Dy and Na have many valuable features such as high sensitivity, tissue equivalence, low fading, non-requirement of annealing and insensitivity to light. Thermoluminescence studies of Dy and Na doped MgB4O7 samples showed that a glow emission peaked at about 195 °C. In this study, the trapping parameters associated with the main dosimetric peak, namely at 195 °C, of Dy and Na doped MgB4O7 are investigated. Isothermal luminescence decay, glow curve shape, initial rise (linear regression) and Tm - Tstop methods were used. We report the results on the kinetic behaviour and activation energy determination of the peak occurring at 195 °C with a moderate heating rate of 2 °C s-1. The average activation energies obtained by the isothermal luminescence decay method, glow curve shape method and initial rise method are calculated to be 1.03 eV, 0.95 eV and 0.89 eV, respectively. The methods mentioned above indicate that the dosimetric peak may consist of one or more second-order components. The frequency factors obtained by the three methods are 3.5 × 1010 s-1, 1.6 × 109 s-1 and 3.4 × 108 s-1, respectively. Results obtained using all these methods are compared and discussed. © 2006 IOP Publishing Ltd.
  • No Thumbnail Available
    Item
    Room and low temperature luminescence properties of CaSO4:Dy,Tm codoped with Li
    (Elsevier B.V., 2009) Can N.; Karali T.; Wang Y.; Townsend P.D.; Prokic M.; Canimoglu A.
    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.