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.
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.
Horowitz
Y S
YS
Physics Department, Ben Gurion University of the Negev, Beersheva, Israel. yigal@bgumail.bgu.ac.il
Einav
Y
Y
Biderman
S
S
Oster
L
L
D005459:Fluorides / Q000737:chemistry / Q000528:radiation effects*; D018020:Lithium Compounds / Q000737:chemistry / Q000528:radiation effects*; D008274:Magnesium / Q000737:chemistry; D055095:Optics and Photonics; D011854:Radiochemistry; D013696:Temperature; D013819:Thermoluminescent Dosimetry / Q000379:methods* / Q000706:statistics & numerical data; D014025:Titanium / Q000737:chemistry
D018020:Lithium Compounds; C027651:lithium fluoride; D014025:Titanium; D008274:Magnesium; D005459:Fluorides