Browsing by Author "Wang, Y"

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Room and Low Temperature Luminescence Properties of CaSO4:Dy,Tm Codoped with Li
    (ELSEVIER SCIENCE BV) Can, N; Karali, T; Wang, Y; Townsend, PD; 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.
  • No Thumbnail Available
    Item
    Enhancing the blue luminescence behaviour of the Li co -doped novel phosphor ZnB 2 O 4: Tm 3+
    (ELSEVIER SCIENCE SA) Kucuk, N; Kaynar, ÜH; Akca, S; Alajlani, Y; Yin, L; Wang, Y; Guinea, JG; Bulcar, K; Dogan, T; Karabulut, Y; Ayvacikli, M; Canimoglu, A; Topaksu, M; Can, N
  • No Thumbnail Available
    Item
    Influence of Li dopants on thermoluminescence spectra of CaSO4 doped with Dy or Tm
    (ELSEVIER SCIENCE BV) Wang, Y; Can, N; Townsend, PD
    Thermoluminescence emission spectra are presented for lithium doped variants of CaSO4:Dy or CaSO4:Tm dosimetry material. All three dopants (Li, Dy and Tm) variously introduce different changes in both the glow peak temperatures and the luminescence efficiency. In every case the emission signals display the line emission characteristic of the rare earth ions. At temperatures below similar to 50 K the relative peak intensities differ for Dy and Tm doped samples, and there are small temperature shifts between the Dy:Li and Tm:Li co-doped materials. Above room temperature the rare earth ions do not show peak temperature movements when co-doped with lithium. However they do influence the peak temperature by similar to 5 degrees C when they are the sole dopant. Inclusion of lithium dramatically moves the high temperature glow peak from similar to 200 degrees C down to 120 degrees C. All these changes are consistent with a single defect model in which the trapping sites and luminescence occur within the complexes formed of the rare earth ion, an intrinsic sulphate defect and lithium. The evidence and rationale for such a model are presented. There is discussion which suggests that such defect complexes are the norm in thermoluminescence. (C) 2011 Elsevier B.V. All rights reserved.
  • No Thumbnail Available
    Item
    Indications of bulk property changes from surface ion implantation
    (TAYLOR & FRANCIS LTD) Wang, Y; Yang, B; Can, N; Townsend, PD
    In the majority of cases, the effects of ion implantation are confined close to the implant zone but, potentially, the resultant distortions and chemical modifications could catalyse relaxations extending into the bulk substrate. Such possibilities are rarely considered but the present data suggest that high dose ion implantation of ZnO has induced bulk changes. Surface implants with Cu and Tb strongly modified the low temperature bulk thermoluminescence properties generated by X-ray irradiation. Suggestions are proposed for the possible mechanisms for bulk relaxations and structural characteristics, which may indicate where such instability may occur in other lattice structures.
  • No Thumbnail Available
    Item