The National Primary Standards

National Primary Standards for measurements of Physical Quantities Related to Ionizing Radiation

The standards developed at the Institute realize the measurement units relevant for ionizing radiation as at the International System of Units.

The standards operating at the Institute comprehends about 20 experimental lines for the absolute measurements of the physical quantities that are related to the use of ionizing radiation.

These measurements assemblies, whose essential characteristics are described in a table of standars (currently available in Italian version of this page), are coupled to irradiation units (alpha, beta, and gamma irradiators, low and medium-energy x-ray units, neutron sources, several radionuclide sources with a special emphasis on radon, etc) with metrological characteristics. The system of national standards allows the absolute measurement of the following physical quantities: Absorbed dose, exposure, dose equivalent (in all its different forms), activity concentration of radionuclides (including radon and its progeny), neutron fluence, etc.

The role of the Institute is to maintain and develop the characteristics of these measurement assemblies at the qualitative levels dictated by the international agreements on primary metrology. These measurements assemblies, necessary for calibrations of present day instruments that measure ionizing radiation, are unique in the country. To maintain their efficiency requires both experimental efforts (detectors, electronics, computational equipment) and numerical efforts as well as expertise in modelling phenomena of interaction of radiation with matter.

The primary standards that are operational at ENEA-INMRI constitute, in the field of ionizing radiation, the national primary standards of the measurement units within the framework of the National Calibration System, instituted in Italy on August 11, 1991, via Law No. 273. The National Calibration System is composed of the Primary Metrology Institutes and the Secondary Calibration Standard Laboratories (ACCREDIA). The primary metrology Institutes in Italy are INRIM and ENEA-INMRI. In turn, the National Calibration System operates according to the networks of the international metrology.

The requirements for the mutual recognition agreement of primary standards and relative calibration certificates, to which ENEA-INMRI must comply, are indicated in the Mutual Recognition Agreement Document of October 14, 1999.