Measurements of delayed neutron parameters for {sup 235}U and {sup 237}Np

Delayed neutrons play an important role in various reactor applications through the effect they have on the kinetic response of a reactor. Delayed neutrons are produced from the decay of nuclei that are formed following the beta decay of fission products better known as delayed neutron precursors. The percent of delayed neutrons emitted is {approximately}1% of the total neutrons emitted from fission; however, this small quantity plays an important role in reactor control. The purpose of this experiment is to measure the delayed neutron period and yield and the delayed neutron fraction for the six groups of delayed neutrons in {sup 235}U and {sup 237}Np. To study the delayed neutron phenomena, a suitable neutron source is required. The bare {sup 235}U metal assembly Godiva IV at Los Alamos Critical Experiment Facility (LACEF) will provide the source of neutrons. Godiva IV will generate {approx}10{sup 10} total fissions in the sample for the `instantaneous` and `infinite` irradiation needed to accentuate, respectively, the shorter and longer periods of delayed neutrons.