An Intercomparison Programme is being carried out in Argentina for individual monitoring services. The programme was designed to test, on a voluntary basis, the performance of the laboratories that provide individual monitoring services for X and gamma radiation fields in the range from low-level dose up to 100 mSv. Irradiations were performed in full accordance with ISO 4037-3 recommendations by the Regional Reference Centre for Dosimetry (CRRD), belonging to Atomic Energy Commission (CNEA) and the Physical Dosimetry Laboratory of the Nuclear Regulatory Authority (ARN). At the same time, several items have been asked to each participant pertaining to the action range, the detectors' characteristics, the laboratory procedures, the existence of an algorithm and its use for the dosemeter evaluation. In this study the evolution of the laboratories' performance throughout the programme, based on ISO 14146 acceptance criteria, is shown.

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In this work, a neutron spectrometric system based on a set of moderating spheres with thermoluminescence detectors (TLD) is presented. The system at the Nuclear Regulatory Authority (ARN) Dosimetry Laboratory consists of 12 solid spheres made of high-density polyethylene (p = 0.95 g x cm(-3)), with diameters ranging from 2" to 12" and TLD sensitive to thermal and gamma radiation, namely TLD-600 and TLD-700, located at the centre of the spheres. The neutron response matrix for this Bonner Sphere Spectrometer (BSS) was calculated using the MCNP-IVB code and the library ENDF/B-VI in the energy range between thermal neutrons and 100 MeV. The neutron spectrum was obtained using the LOUH182 unfolding code. The improvement in sensitivity of the system is based on the election of a different heating cycle of the TLD that allows an increase in sensitivity by a factor of 2.6 compared with the standard laboratory treatment. The system response for the calibration with an Am-Be source is presented.

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