Results of two Albedo systems in a Brazilian neutron individual monitoring comparison

In 2012, the Brazilian National Metrology Laboratory sponsored the First Brazilian National Comparison of Measurements with Neutron Individual Monitors. The Thermoluminescent Dosimetry Laboratory of the Institute of Radioprotection and Dosimetry IRD/CNEN-RJ participated in it with its two albedo systems: one-component and two-component albedo monitors. The one component is composed by two capsules in a belt and each capsule has a pair of TLD for albedo neutron detection. The two-component consists of one capsule in a belt with two pairs of TLD: one pair for the measurement of the incident neutrons and the other for albedo neutrons. This paper presents the results of both systems in that comparison. The irradiation of the monitors was performed in four different values of Hp(10,0 deg) in a traceable 241Am-Be ISO standard reference neutron field. For both systems, it was observed that the evaluated dose values are very close to the reference dose values which each monitor has been undergone. Considering the mean values, the two-component albedo monitor has performance a little bit better than the one-component one but the results of both systems are statistically equal. For both systems, the responses are close to 1 and inside the trumpet curves. Thus, the results of two systems confirm their good accuracy and reproducibility in the tested neutron field and indicate that are able to evaluate the occupational neutron doses. This work confirms the importance of the inter-laboratory comparison programs to verification of the reliability of individual monitoring systems. (author)