Dose-average linear energy transfer of electrons released in liquid water and LiF:Mg,Ti by low-energy x-rays, Cs and Co gamma.

For many years, track-average linear energy transfer (LET), [Formula: see text] has been used to quantify the radiation-induced phenomena in biological and physical systems. However, due to the need for including into the radiotherapy treatment planning system, parameters that are clinical and biologically relevant, a precise knowledge of the dose-average LET, [Formula: see text] becomes essential. Besides, several dosimetric studies have revealed that [Formula: see text] is fundamental to describe the dosimeter's response induced by photons. The most important data sets publicly available for [Formula: see text] of electron generated by photons are those reported for measurements performed in methane-based tissue-equivalent gas. However, comparing to liquid water, the electron spectra generated by low photon energy might not be similar due to the photoelectric effect. Thus, this work aimed at investigating the [Formula: see text] of electron spectra generated in liquid water and LiF:Mg,Ti by ten x-ray beams from 20 kV to 300 kV, Cs and Co gamma. The results suggest that [Formula: see text] is more sensitive to the surrounding environment than [Formula: see text] and consequently, it might be a more appropriate parameter to quantify the radiation effect and damage in matter induced by photons. Besides, good agreement (6% to 12% differences versus 10% to 15% uncertainties in the experiments) was observed between the data obtained in this work for liquid water and the experimental values published for methane-based tissue-equivalent gas at energies above 60 keV. Whereas at lowest energies, the minimum difference is around 18% which can be associated to the difference between the two media.