Determination of the response to photons and thermal neutrons of new LiF based TL materials for radiation protection purposes

LiF based thermoluminescent materials are the most used passive detectors in the field of radiation protection. For personal and area dosimetry in mixed neutron and photon fields, ⁶LiF and ⁷LiF TLD pairs are employed for the simultaneous determination of neutron and photon doses. Therefore, an accurate knowledge of their sensitivity to photons and thermal neutrons is essential. Aimed at providing reliable sensitivity data for new LiF based TL materials, an experimental study was performed in the framework of collaboration between INFN Frascati National Laboratories and ENEA, Italy. The ⁶LiF(Mg, Cu, P) material from TLD Poland, was specially manufactured in six versions with different sensitive thickness (t=40,60,80,100,150 and 230 mg·cm^-2), which implies different neutron and photon sensitivity. Together with the ⁷LiF(Mg, Cu, P) material, namely MCP-7, all seven type of TLDs were irradiated in reference beams of photons and thermal neutrons, at the calibration facilities of INFN and ENEA. The study provides a set of sensitivity data and discusses the performance of the investigated materials for the dosimetry of mixed neutron and photon fields. All uncertainties or error bars reported in the paper refer to 95% confidence level (2 sigma).