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 2012 in order to obtain the energy-dependent multiplicity distributions for the neutron induced fission of ~(235)U. Using the WNR beam and the LANSCE facility we took data in the range from a few hundred keV to several hundred MeV in incident neutron energy. The measurements are performed with an array of organic liquid scintillators covering approximately 11% of 4pi steradians and a digital data acquisition system which allows us to obtain higher neutron multiplicities and to cover a wider range of outgoing angles than previously achieved. The detectors exhibit excellent pulse shape discrimination, allowing gamma-ray events to be rejected. The separation of neutron and gamma events via PSD can be reliably performed down to 100’s of keV. Our analysis has of the average prompt neutron multiplicity shows a continually increasing value as energy increases beyond what has been previously measured.