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Electronic Trap Defects in Y2O3:Eu and (Y,Gd)2O3:Eu X-Ray Scintillators

Published online by Cambridge University Press:  21 February 2011

Steven J. Duclos
Affiliation:
General Electric Corporate Research and Development, Schenectady, NY.
Charles D. Greskovich
Affiliation:
General Electric Corporate Research and Development, Schenectady, NY.
Chester R. O'clair
Affiliation:
General Electric Corporate Research and Development, Schenectady, NY.
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Abstract

Detailed properties of the defects and energy transfers responsible for afterglow in transparent sintered ceramic Y2O3:Eu and (Y,Gd)2O3:Eu based scintillators have been determined by transient thermoluminescence ('TL) and spectral measurements of afterglow emission. X-ray excited TTL spectra between 150 K and 350 K reveal 4 defect transitions for 3 mole percent Eu. Adequate modeling of this data requires for each defect transition a trap depth energy, an attempt-to-escape frequency, a broadened density of trap state energies, and a trap filling frequency. These defect parameters have been determined and can be used to predict afterglow dependence on time after excitation shut-off, exposure time, and temperature. The afterglow emission spectra at all temperatures are characteristic of Eu under S6 site-selective UV excitation of these rare-earth C-type structure scintillators. This indicates that states associated with the Eu activator on the S6 site are the terminal states upon thermal release of trapped charge carriers.

Type
Research Article
Copyright
Copyright © Materials Research Society 1994

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References

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