Charge carrier and exciton dynamics in LaBr{sub 3}:Ce{sup 3+} scintillators: Experiment and model
- Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)
The scintillation yield and decay time of LaBr{sub 3} doped with 0.2%, 0.5%, and 5% cerium were studied between 80 K and 600 K. LaBr{sub 3}:5%Ce{sup 3+} on a photomultiplier tube shows at 300 K a very high scintillation yield of 22 800 photoelectrons per MeV (64 000 photons per MeV) with a decay time of 16 ns. At 600 K the yield decreases by {approx_equal}15%. The scintillation yield of LaBr{sub 3}:0.2%Ce{sup 3+} is 19 800 photoelectrons per MeV (56 000 photons per MeV) at 300 K with a decrease by {approx_equal}50% at 600 K and a main scintillation decay time around 30 ns. The appearance of slow components in the Ce emission indicates a relatively slow energy transfer from the host crystal to Ce. The presence or absence of slow components depends on both concentration and temperature. The results are analyzed and interpreted with a model that comprises prompt charge carrier trapping by Ce and delayed excitation of Ce by means of thermally activated transport of self-trapped exciton defects. The results of the study provide detailed information on the scintillation mechanism. Besides presenting experimental data, the different energy transfer processes are quantified.
- OSTI ID:
- 20951413
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 75, Issue 18; Other Information: DOI: 10.1103/PhysRevB.75.184302; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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