Comparison of the methods for neutron spectra reconstruction

To measure neutron spectra in cores and near the vessel space of nuclear reactors the activation method is used. The method is based on the measurement of certain activation integrals for different reactions with the known cross sections. The problem has a variaty of solutions. Selection of the only solution is determined by the initial spectrum assignment. The Perey least square method is compared with that of the Najzer iteration method ITER as regards sensitivity to the initial spectrum. The conclusion is made that ITER algorithm provides solution of the problem which is close to the actual one