Activity measurement 103Rhm X-ray emitting radio-isotope: Application to experimental programs carried out in the CEA critical facilities

International benchmarks for cross-sections qualification are very poor in experimental means able to provide information on the neutron spectrum around 1 MeV. To fill this vacancy, one possible solution is to use the activation of rhodium. The reaction of inelastic neutron scattering on this element, in the energy range of 0.5 MeV to 5 MeV, leads to the formation of ¹⁰³Rh^m. The return to the ground level of this radionuclide emits X-rays of low energy. This paper describes a method for determining the activity of ¹⁰³Rh^m taking into account the constraining characteristics of this radionuclide and proposes a computed to measured results comparison for an experiment irradiated in the French CEA critical facility EOLE.