Abstract
The composite structure of glow peak 5 in LiF:Mg,Ti (TLD-100) has been investigated using optical bleaching by 310 nm (4 eV) light. The decay of composite peak 5 and the simultaneous growth of peak 4 are described by two exponential components of the same mean life for both peaks. The conversion of peak 5 to peak 4, as a function of the temperature of post-irradiation annealing, reveals that the conversion efficiency of charge from peak 5a traps to peak 4 traps is very high (30%) whereas the conversion efficiency from peak 5 traps to peak 4 traps is no greater than a few percent. Glow peak 5a is believed to arise from geminate recombination of a locally trapped electron-hole pair in a spatially correlated trapping center (TC) and luminescent center (LC). Glow peak 5 results from recombination via electron diffusion in the conduction band following thermal release of a singly trapped electron in the TC/LC structure. Glow peak 4 arises from a singly trapped hole in the TC/LC structure. The high conversion efficiency of peak 5a to peak 4 arises from direct optical ionisation of the electron in the electron-hole pair, leaving behind a singly trapped hole (peak 4), a direct mechanism relatively free of competitive processes. Optical ionization of the 'singly trapped' electron (peak 5), however, can lead to peak 4 only via multi-stage mechanisms involving charge carrier transport in the conduction band, a mechanism subject to competitive processes, which leads to an order of magnitude decrease in the observed conversion efficiency.
Original language | English |
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Pages (from-to) | 552-554 |
Number of pages | 3 |
Journal | Journal of Luminescence |
Volume | 87 |
DOIs | |
State | Published - 1 Jan 2000 |
Event | International Conference on Luminescence and Optical Spectroscopy of Condensed Matter (ICL'99) - Osaka, Jpn Duration: 23 Aug 1999 → 27 Aug 1999 |
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- General Chemistry
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics