Argentina Neutron Calibration Center

In Argentina, Nuclear Regulatory Authority (ARN in Spanish) has a neutron irradiation facility for personnel dosimetry research, dosimetry intercomparison studies, dosimetry performance test programs, training of health physics and safeguards personnel, and radiobiology research. The facility, established to support regulatory activities, is located at Ezeiza Atomic Center far away from other facilities in order to avoid the use of shielding when it operates. The laboratory dimensions are: 14m long, 6m wide, and 4m high and the roof and walls are made of galvanized plate steel. The steel building is mounted on a 15cm thick concrete floor directly on the ground. The laboratory consists of a neutron irradiator with the capability to contain two sources and a pneumatically operated carousel for selecting the sources, located in a shielded design below ground level, to fit in a 12' pipe 2 m deep. The exposure position is 2m over the floor. The sources are Cf-252 (1.45108 n/s) and AmBe (1.13 e+107 n/s); the 252Cf source can be used either bare or surrounded by heavy water (D2O). The facility has been completed with a calibration bank made of aluminium, 6m long, 1m wide, and 1.5m high and a track system for movement of phantoms or detectors. The laboratory's scattering was studied for the 252Cf and 252Cf + D2O sources, in free air irradiation conditions, with the MCNPX -V2.5f code, resulting in a contribution of less than 10%. This value was experimentally validated for a 252Cf source. The facility's neutron reference fields were calibrated for 252Cf (bare and moderated with heavy water) by Los Alamos National Laboratory (LANL; USA) using a ROSPEC II transfer detector, which was calibrated by PTB in the thermal region and by National Institute of Standards and Technology (NIST) up to 20 MeV. The Neutron Calibration Center (NCC) was established in the framework of a collaboration programme between ARN and DOE-ORNL. (author)