[en] The latest achievements in fluorescent nuclear track detector (FNTD) technology are described. FNTDs are aluminum oxide crystals containing aggregate oxygen vacancy defects and doped with carbon and magnesium (Al₂O₃:C,Mg). Unlike most nuclear track detectors, Al₂O₃:C,Mg is sensitive to low linear energy transfer (LET) radiation including secondary electrons resulting from interactions of photons with the crystal. A new image processing method is investigated as a technique to discriminate and measure the doses of gamma and fast neutrons in mixed field conditions. Dose dependencies for both gamma and neutron irradiated FNTDs are shown. The new image processing method increased the dynamic range of detectable neutron doses from 4 orders of magnitude for track counting method to at least 6 orders of magnitude by combining track counting with the new image processing method. The new image processing method is combined with a detector configuration utilizing three converters: Teflon, polyethylene, and lithium fluoride.