Induced fission and signature studies of actinide isotopes using ANL/IPNS thermal neutrons and an array of detectors

Since the mid-1980s when multidetector arrays of high-purity germanium (HPGe) detectors became available, several studies of the prompt fragments from spontaneous fission of {sup 252}Cf, {sup 242}Pu, and {sup 235}U have been undertaken. The data from these measurements have formed the basis of new insights into the fission process. The current series of experiments is aimed at collecting information on the prompt fission fragments arising from thermal neutron-induced fission. The first experiment uses an array of compton-suppressed HPGe detectors and fast liquid scintillation detectors to observe the radiation emitted from the induced fission of {sup 235}U with a beam of thermal neutrons. The experiment was performed at the Argonne National Laboratory Intense Pulsed Neutron Source. A target of {approximately}2 g of uranium was used for this measurement. The array gathers multiple types of time-correlated radiation data. These fission studies and their new results are the basis of an NDA system under development to measure fissile mass, fissile isotopic ratios, radiation source term, and specific fission product isotopes. This system will have applications for the National and Idaho National Environmental and Engineering Laboratory (INEEL) SNF Programs, the Advanced Mixed Waste Focus Area, the Transuranic Waste Program, the safeguards and Security Office,more » and the Nonproliferation and National Security Office.« less