|Search for content and authors|
Influence of structural defects upon electrophysical and scintillation characteristics of wide band gap ZnSe(Te) crystals for UV sensors and X-ray detectors
|Iryna A. Rybalka , Sergiy M. Galkin , Volodymyr D. Ryzhikov , Yevgen F. Voronkin , Oleksandr I. Lalaiants|
Institute for scintillation materials of NAS of Ukraine (ISMA), Lenin avenue, 60, Kharkov 61158, Ukraine
ZnSe crystals are widely applied in the modern multichannel low-energy radiation devices of X-ray image visualization (medical tomographs, customs introscopes, devices of antiterrorist purpose, etc.), and in UV sensors as Shottky diode.
The work is devoted to research of possibility of obtaining of ZnSe crystals by Bridgman method with a high level of the structural perfection, the increased mechanical strength and the established electrophysical and scintillation parameters for use in the radiation detectors.
In this work it is investigated the impurity composition of ZnSe(Te) charge and crystals grown up in the graphite crucible at isovalent doping by ZnTe, and the analysis of possible ways of their contamination by chemical impurities is carried out. Influence of the chemical purity of initial raw material, ZnSe(Te) crystal growth conditions on the formation of structural defects of the different type (dislocations, twin boundaries, etc.) is determined.
Influence of tellurium doping on the structural perfection, electric properties and scintillation parameters of ZnSe(Te) crystals is studied. The optimum mode of thermal treatment of ZnSe crystals is determined, that on condition of tellurium doping with 0,3...0,6 % concentration range has allowed to obtain scintillators with a high level of structural perfection (blende free of packing defects), the increased mechanical strength (increase in breaking point on ~ 20 % in comparison with undoped ZnSe), the specified light output (within of 110-120 % relatively CsI(Tl)), time decay 5-10 ms and afterglow less 0,005 % through 10 ms after X-ray action. It has enabled in Institute for Scintillation Materials to create pilot production of ZnSe(Te) scintillation crystals corresponding to the best world samples for the introscopes and medical tomographic equipments.
This work was supported by the U.S. Civilian Research and Development Foundation (CRDF) and NATO Science for Peace and Security Program (Project SfP-982823).
Presentation: Poster at E-MRS Fall Meeting 2009, Symposium C, by Iryna A. Rybalka
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-10 18:03 Revised: 2009-07-17 16:50