Multiplicity Distributions and Energy-Angle Correlations in Spontaneous Fission Neutron Emissions

Measurements were performed at the Los Alamos Neutron Science Center (LANSCE) in fall of 2010 in order to measure fission neutron spectrum of the fissile isotope 235 U. Extensions are planned to additional isotopes such as 239 Pu and the analysis will be extended to cover the multiplicity distribution as well as to obtain energy-angle correlation data. The methodology is being developed at our laboratory at the University of Michigan. The measurements that have been performed utilized several organic liquid scintillators (EJ-309) and a digital data acquisition system in order to measure higher order multiples and to cover a wide range of angles for the correlation measurements. Using the well-known multiplicity distribution of 252 Cf we can use our data to calculate the different moments of the measured distribution and to match it to the known distribution and determine correction factors to be used in our past measurement. Using time-of-flight we can determine the incident neutron energy at each detector and by knowing the angle of all detectors relative to each other we examine the correlation of neutron energy and angle of emission.