On the photon self-absorption correction for thin-target-yields vs. thick-target-yields in radionuclide production

In the experimental determination of activity of low gamma energy emitters by HPGe spectrometry, after cyclotron irradiation of thick targets of high Z elements, it is mandatory to introduce a correction for gamma-ray self-absorption in the target. The amount of this correction is substantial in order to provide a statistically acceptable agreement with the thick-target-yield data obtained by integration of the experimental thin-target-yield data that are very slightly affected by self-absorption instead.