AbstractA very efficient detector able to measure both electron and photon heats simultaneously and separately has been developed at ENEA Frascati. The detector consists of a well-type 22.8×22.8 cm2 CsI scintillator (for photon detection) and a small plastic electron detector inserted in the well. This system has been used to measure the decay heat induced in 15 natural elements, irradiated with 14 MeV neutrons. The experimental results have been used to validate the calculation code system EASY-2001, especially developed for the prediction of induced radioactivity in fusion devices. The Calculation versus experiment (C/E) results are reported. For those results where deviations from the C/E=1 line were found, outside the experimental uncertainty band, new effective (integral) cross-sections are proposed, able to bring the results inside the uncertainty estimations. The new cross-section values are discussed in the text.