Afterglow kinetics and storage mechanism in CaF2:Mn (TLD-400)

Effect of annealing and impurity concentration on the TL characteristics of nanocrystalline Mn-doped CaF2

“…However, there are some drawbacks, such as, complicated glow curve structure, low stability and fast fading, loss of reusability, etc. (Danilkin et al, 2008). One of the main disadvantages of CaF 2 :Mn is its low stability, on annealing and during repeated TL readouts, introducing inaccuracies in dose measurements.…”

“…It is caused by a strong dependence of TL glow curve structures on the concentration of the impurity (Mn) and its related redox reactions during annealing. It is believed that low stability of the phosphor is caused by the oxidation of Mn 2þ to higher charge states at higher temperatures (Danilkin et al, 2008;Planque, 1984). However, a well defined and simple hightemperature TL peak is observed when concentration of Mn ions is very close to the threshold concentration (~3.0 mol%).…”

“…Earlier, several workers have investigated the material (CaF 2 :Mn) and tried to understand TL processes and defects (Danilkin et al, 2008;Planque, 1984;Lust, 2007;Horowitz, 1984;McKeever, 1985;McMasters et al, 1987;Danilkin et al, 2006;McKeever et al, 1986). But the lack of clear knowledge about the TL mechanism, defects formation and their instability at high temperatures showed that the system (CaF 2 :Mn) is yet to be fully understood.…”

“…If it is the case, indeed, then the phosphor should be very stable but it has been found to be otherwise. The same group further tried to explain the changes in the glow curve structures due to 'jumps' of the fluorine ions into interstitials and forming the neutral F 2 molecules storing the energy and releasing it on their dissociations again changing the activation energies and the glow curve structure (Danilkin et al, 2008). But, it seems it is not the stress or the fluorine ions only but 'something else' that might also be contributing to it.…”

Fabrication, properties and thermo-luminescent dosimetric application of CaF2:Mn transparent ceramic

“…It also leads to variations in the Mn concentration throughout the crystal. Hence, most of the reports on this material are either on polycrystalline powder samples or pellets [10,11]. The difficulty in the growth of single crystals can be circumvented by using optically transparent ceramics (OTC) of this compound.…”