Neutron Multiplicity Distribution Measurements of ~(235)U Induced Fission

摘要

Measurements were performed at the Los Alamos Neutron Science Center in the fall of 2012in order to obtain the energy-dependent multiplicity distributions for the neutron inducedfission of ~(235)U. Using the WNR beam and the LANSCE facility we took data in the range froma few hundred keV to several hundred MeV in incident neutron energy. The measurements areperformed with an array of organic liquid scintillators covering approximately 11% of 4pisteradians and a digital data acquisition system which allows us to obtain higher neutronmultiplicities and to cover a wider range of outgoing angles than previously achieved. Thedetectors exhibit excellent pulse shape discrimination, allowing gamma-ray events to berejected. The separation of neutron and gamma events via PSD can be reliably performeddown to 100’s of keV. Our analysis has of the average prompt neutron multiplicity shows acontinually increasing value as energy increases beyond what has been previously measured.