Expansion of the capacities of the Neutron Standards Laboratory at CIEMAT

The Neutron Standards Laboratory (LPN) belonging to the Ionizing Radiation Metrology Laboratory (LMRI) of the Research Centre for Energy, Environment and Technology, CIEMAT, is the depositary of the national neutron fluence standards that are materialized in the neutron sources belonging to the laboratory, a ²⁵²Cf source of 236 µg, calibrated at NIST (USA) and a ²⁴¹Am-Be source of 185 GBq, calibrated at CMI (Czech Rep.). Therefore, neutron sources constitute secondary standards and services of calibration for area and personal neutron dosimeters are provided with them. 

With the expansion of the LPN, a primary standard will be built, which will allow the absolute calibration of neutron sources, both own and external, through the technique of the Manganese Bath. Its implementation will make us primary laboratory, promoting the metrological independence of our country in this field. 

A new thermal neutron field will also be incorporated, based on graphite pile with dimensions of 150 cm high by 150 cm width and 180 cm depth with an ²⁴¹Am-Be source of 185 GBq, and a cavity of 30 cm x 30 cm section and 40 cm depth. This will allow increasing the neutron fields in which we can calibrate currently that cover the fast range, with ²⁵²Cf and ²⁴¹Am-Be, and the epithermical range, with heavy water moderated  252Cf, with the incorporation of the thermal range. In this way we will offer technical calibration services throughout the energy range recommended by ISO 8529-1, with the exception of monoenergetic neutron beams, for which it is necessary to count with accelerators.