Photon radiation and the air kerma rate constants of 152Eu and 154Eu radionuclides

It is often required to estimate the kerma rate at a distance from the radionuclides sources emitted photon radiation such as, for instance, 152Eu and 154Eu which represents frequently used sources in many fields of science, technology and medicine. The factor relating activity and air kerma is the air kerma rate constant - γβ. Analysis of accessible data on this quantity for mentioned radionuclides led us to the conclusion that discrepancies in reported calculated values exist because the radionuclides decay scheme and other nuclear spectroscopy data pertinent to these calculations were not well known. That is the reason we calculated these quantities on the basis of our methodology, nuclear spectroscopy data given by many authors and the latest data for the mass-energy transfer coefficients for air. In this way the air kerma rate constants are calculated to be 41,1 ± 0,6 aGy m2 s-1 Bq-1 for 152Eu and 44,1 ± 0,2 aGy m2 s-1 Bq-1 for 154Eu. Calculation was made for the unfiltered point source including emitted photon radiation with energies greater than 20 keV and yield per decay event higher than 0,05%. (author)