Reevaluation of Prompt Neutron Emission Multiplicity Distributions for Spontaneous Fission

The prompt neutron emission probability distributions and average values (P and <>, respectively) for nuclei that decay via spontaneous fission have been reevaluated to determine if any significant gaps in the fundamental nuclear data exist that could affect the development of the safeguard approach for the Global Nuclear Energy Partnership. The reevaluation incorporated measurements that have been performed over the past two decades and has yielded revised prompt <> consensus values for ²⁵⁶Fm of 3.848 ± 0.027 and for ²⁵²No of 4.25 ± 0.25. Updated consensus P values were also created for ^244,248Cm, ²⁵²Cf, ^254,256Fm, and ²⁵²No.