Localised and delocalised optically induced conversion of composite glow peak 5 in LiF:Mg,Ti (TLD-100) to glow peak 4 as a function of postirradiation annealing temperature

• Published in: Radiation protection dosimetry Vol. 100; no. 1-4; p. 135
• Main Authors: Horowitz, Y S, Einav, Y, Biderman, S, Oster, L
• Format: Journal Article
• Language: English
• Published: England 2002
• Subjects: Fluorides - chemistry; Fluorides - radiation effects; Lithium Compounds - chemistry; Lithium Compounds - radiation effects; Magnesium - chemistry; Optics and Photonics; Radiochemistry; Temperature; Thermoluminescent Dosimetry - methods; Thermoluminescent Dosimetry - statistics & numerical data; Titanium - chemistry
• ISSN: 0144-8420
• DOI: 10.1093/oxfordjournals.rpd.a005831

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 glow peak conversion efficiency of peak 5a (Tm = 187 degrees C) to peak 4 traps is very high at a value of 3+/-0.5 (1 SD) whereas the glow peak conversion efficiency of peak 5 (Tm = 205 degrees C) to peak 4 traps is 0.0026+/-0.0012 (1 SD). 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 mechanisms. Optical ionisation of the 'singly-trapped' electron (peak 5), however, can lead to peak 4 only via multi-stage mechanisms involving charge carrier transport in the valence and conduction bands, a mechanism subject to competitive processes. The conduction/valence band competitive processes lead to the factor of one thousand decrease in the conversion efficiency of peak 5 compared to peak 5a.