A Flexible And Modular Fast Neutron Multiplicity Counter For Correlated Nuclear Data Research

Steven A. Dazeley - Lawrence Livermore National Laboratory
Viacheslav A. Li - Lawrence Livermore National Laboratory
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We describe a new form of flexible multiplicity counter to address gaps in fission nuclear data by measuring a broad range of correlated neutron and gamma-ray signatures with high angular and energy fidelity. The detector consists of independent modules of 6Li-doped pulse shape discriminating (PSD) plastic scintillator, sensitive to both fast and thermal neutrons. The modules will be between 0.5 and 1 meter in length and with a 5 - 10 cm square cross section. The proposed length scales reflect the intrinsic attenuation lengths achievable in 6Li-doped PSD plastic. The modules will contain no liquid scintillator, will be rugged and easily movable and reconfigurable around a central test fission source. The anticipated position sensitivity within each module is expected to be at the same level as the cross section (~5 - 10 cm). The angular uncertainty will depend on the distance of each module from the test fission source. The modules may be placed at greater distance from a source to optimize for time-of-flight fidelity or adjacent to the source to optimize detection efficiency. Modules may be mixed and matched with gamma-ray detectors or 3He tubes to address different gaps in nuclear data as required. The whole system may be scaled to any number of modules in principle if very high efficiencies are required.This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344, release number LLNL-ABS-819628