Using anisotropies in prompt fission neutron coincidences to assess the neutron multiplication of highly multiplying subcritical plutonium assemblies [electronic resource]
Saved in:
| Online Access: |
Online Access (via OSTI) |
|---|---|
| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. National Nuclear Security Administration ; distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2016.
|
| Abstract: | There is a significant and well-known anisotropy between the prompt neutrons emitted from a single fission event; these neutrons are most likely to be observed at angles near 0° or 180° relative to each other. However, the propagation of this anisotropy through different generations of a fission chain re-action has not been previously studied. We have measured this anisotropy in neutron-neutron coincidences from a subcritical highly-multiplying assembly of plutonium metal. The assembly was a 4.5 kg α-phase plutonium metal sphere composed of 94% <sup>239</sup>Pu and 6% <sup>240</sup>Pu by mass. Data were collected using two EJ-309 liquid scintillators and two EJ-299 plastic scintillators. The angular distribution of neutron-neutron coincidences was measured at 90° and 180° and found to be largely isotropic. Simulations were performed using MCNPX-PoliMi of similar plutonium metal spheres of varying sizes and a correlation between the neutron multiplication of the assembly and the anisotropy of neutron-neutron coincidences was observed. In principle, this correlation could be used to assess the neutron multi-plication of an unknown assembly. |
|---|---|
| Item Description: | Published through SciTech Connect. 07/01/2016. ": S0168900216301917" Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment 825 C ISSN 0168-9002 AM. Mueller, J.; Mattingly, J. Univ. of Michigan, Ann Arbor, MI (United States) |
| Physical Description: | p. 87-92 : digital, PDF file. |