The measurement of the activity of X-ray emitting radionuclides, in the energy range below 100 keV, presents several difficulties that limit the accuracy of the result. Among the important applications of the measurement of X-ray emitters, the dosimetry in reactor, which allows to determine the neutron fluence received during an irradiation and to characterize the spectrum, is based on the analysis of the activity of irradiated dosimeters. These dosimeters are made of pure metals or alloys of perfectly known composition, some of which are subject to activation or fission reactions under the effect of neutrons. For example, the reactions 93Nb(n,n')93mNb and 103Rh(n,n')103mRh are particularly interesting for characterizing neutron fluxes around 1 MeV. The task of the postdoc will consist in:

i) Exploiting the results of the efficiency calibration of a high purity germanium (HPGe) detector using a cryogenic electrical substitution radiometer and transfer photodiodes. This will be used to measure the absolute X-ray emission intensities of radionuclides used as standard for the calibration of detectors (133Ba, 152Eu, etc.);

ii) Improve the knowledge of photon emission intensities following the decay of 93mNb, 103Pd and 103mRh;

iii) Critically analyzing published data on these radionuclides and contributing to the evaluation and publication of their decay schemes.