Use of an annular241Am−Be neutron source for INAA of some major constituents in large samples

Abstract: An annular neutron source offers the possibility of positioning a large sample, surrounded by a paraffin thermalizing shield, inside the central tube. The optimal shield/sample ratio is determined experimentally. The absolute value of the thermal neutron flux is determined by irradiating NaHCO₃ and evaluating the induced²⁴Na-activity by the sumpeak method. Average fluxes over the seven irradiation capsules are presented. Some current applications are discussed.