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II-VI compound phosphors for modern X-Ray applications
|Oleksandr I. Lalaiants , Sergiy M. Galkin , Vladimir D. Ryzhikov , Iryna A. Rybalka , Yevgen F. Voronkin , Igor A. Breslavskiy|
Institute for scintillation materials of NAS of Ukraine (ISMA), Lenin avenue, 60, Kharkov 61158, Ukraine
It is known that several A2B6 compounds have high temperature stability, radiation hardness, phosphor properties and therefore scintillation and optoelectronic applications. Thus, ZnS crystals use as phosphor in light-emitting and detective devices. The ZnSe crystals apply as X-Ray- and gamma- detectors in medical homographs and airport security systems. The optical and electrical parameters of these crystals depend on structure of defective complexes. These complexes have the spatially-periodic structure.
We have studied the optical and scintillation parameters of ZnSe crystals grown by Bridgman method. We have studied the structure of luminescence centers and the emission mechanism in ZnSe with donor dopants. Thus luminescence at 300 K is conditioned by defective complexes Donor-VZn-Zni in ZnSe crystals.
The donor-doped ZnSe crystals are characterized of following parameters:
The “scintillator-photodiode” detectors are applied in the majority of the modern computer tomographs. A broad dynamic range (103-104) and a small aperture are typical for these detectors.
These parameters determine the high spatial resolution of tomography systems. The short decay time and low afterglow of scintillators are necessary for rapid signal counting from great number of detectors (1000 channel and more). The afterglow must be within (0.001-0.01) % after 10 ms of X-Ray pulse.
These research results have allowed to develop reproducible technology of ZnSe scintillator production for application in inspection and medical 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: Oral at E-MRS Fall Meeting 2009, Symposium C, by Oleksandr I. Lalaiants
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-10 17:17 Revised: 2009-07-17 16:47