Reconstruction of gamma-ray source activity in a multiple samples set-up

When numerous radioactive samples irradiated simultaneously have to be measured using a single photon detector, the resulting energy spectrum comprises not only the yield from the source closest to the detector but also from all other sources. This case is particularly important when the sources are placed in a set-up exchanging them in an automated manner. In order to obtain relevant data for each source, correction procedures were developed and tested via Monte-Carlo simulations and with radioactive sources, in a set-up with up to 16 samples placed on a rotating wheel. In a test experiment, the cross-section of 12C(p, X)11C (X=d or pn) was determined using a stack of 15 carbon targets irradiated with a proton beam of initial 58 MeV kinetic energy. The 11C activity of simultaneously irradiated targets was measured (through 511 keV photons) and reconstructed using the developed correction procedures. The results of cross-section measurements are in agreement with the previous experiments, supporting the correctness of the reconstruction procedure.