TL response of pairs of 6 LiF:Mg,Cu,Si/ 7 LiF:Mg,Cu,Si and TLD-600/TLD-700 to 0.1–12 MeV neutrons

Neutron dosimetery continues to remain an important and a challenging aspect of radiation protection due to the higher biological effectiveness of neutrons than that of gamma rays and the intricacy in the responses of the detectors. The need for personal dosimetry in mixed fields of neutrons and gamma rays has considerably increased due to the rising number of nuclear facilities, nuclear power plants, medical therapy equipment, accelerators and so on. The most widely used technique for personal dosimetry has been the albedo technique employing pairs of neutron sensitive 6LiF:Mg,Ti (TLD-600) and neutron insensitive 7LiF:Mg,Ti (TLD-700) thermoluminescent dosimeters (TLDs). Off late, LiF:Mg,Cu,Si has emerged as one of the most promising TLD material, having the advantages of high sensitivity, near tissue equivalence to gamma rays, negligible fading on pre and post-irradiation storage, thermal stability for readout and negligible residual signal after the readout. In this study, neutron energy response of indigenously developed 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLD pairs was evaluated to neutrons of energy from thermal to 11.6 MeV and was compared with the response of TLD-600 and TLD-700 pairs. The net TL per unit neutron dose for the 6LiF:Mg,Cu,Si/7LiF:Mg,Cu,Si TLD pair was found to be about 10 times of that of the TLD-600/TLD-700 pair. Unlike, TLD-600 and TLD-700, the glow curve structure of 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si remained almost the same for all the irradiations. Thus, 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLDs provided a better alternate to TLD-600 and TLD-700 for the dosimetry of mixed fields of neutrons and gamma rays.