Application of LiF fluorescent nuclear track detectors for measurements of cosmic radiation at the lunar orbit within the MARE experiment

A method for reconstructing linear energy transfer (LET) fluence spectra of a complex cosmic radiation field using LiF-based fluorescent nuclear track detectors (FNTD) was developed. It is based on the relationship between track intensity and LET and includes corrections for the particle’s angle of incidence. The method was successfully applied to the analysis of the detectors exposed to radiation at lunar orbit in the frame of the MARE project (part of the NASA Artemis I mission). The obtained spectra were compared with the data from etched plastic nuclear track detectors (PNTD), which were located in the same places as FNTDs. The spectra measured with both detector systems agreed, with the exception of LET H2O >100 keV/μm, where FNTD overestimated the PNTD. This, in turn, caused overestimation of the dose (by up to 30%) and quality factor (by about 15%). When calculations were restricted to LET H2O <100 keV/μm, the agreement was within a few percent for dose and within 15% for quality factor.