The concept of quasi-tissue-equivalent nanodosimeter based on the glow peak 5a/5 in LiF:Mg,Ti (TLD-100)

SYNTHESIS OF LIF:MG,TI NANOPARTICLES BY CO-PRECIPITATION METHOD AND EVALUATION OF INCREASING THE 5A/5 RATIO IN ALPHA AND GAMMA RADIATION

The peak 5 in LiF: Mg, Ti includes sub-peaks 5a and 5b, which occur at the temperatures lower and higher than that of peak 5, respectively. Peak 5a in LiF:Mg,Ti occurs due to the localized recombination of trapping/luminescence center (TC/LC), in which the electron is released from the electron trap by obtaining energy from heat and recombines through the tunneling phenomenon with a hole located in the adjacent luminescence center at a distance of 3 nm. Concerning the standard TLD tablets, which are composed of micron-sized particles, the peak 5a either does not occur or appears with very low intensity, which is insignificant in terms of dosimetry. Thus, the present study focuses on synthesizing thermoluminescent nanoparticles by co-precipitation method in several stages by citing models based on the maintenance of linear behavior of thermoluminescence nanopowders up to high doses and its relationship with localized electron-hole recombination. In addition, by changing the concentration of ingredients, altering the temperature of the reaction medium and presence or absence of surfactant, nanoparticles with suitable geometric shapes were achieved. The synthesized nanopowders were irradiated with different doses of alpha and gamma, and after analyzing the glow curves, the increase in peak 5a/5 was reported as the main factor in nanodosimetry. Based on the results, the LiF: Mg, Ti thermoluminescence nanopowders can increase the 5a/5 ratio and can be used as a convenient, inexpensive and practical tool to estimate the amount of energy deposited by the beams in nanoscale.