Mass and Nuclear Charge Distributions from the Spontaneous Fission ofFm254

Abstract

The relative fission yields of 20 mass chains from ${}_{}{}^{254}{}_{}{}^{}\mathrm{Fm}$ spontaneous fission were measured by direct high-resolution $\gamma$-ray spectroscopy of the gross fission products. Reflected yields were calculated based on a prompt-neutron fission yield of 3.94; the absolute yields were determined by requiring the sum of all yields to be 200%. A peak-to-valley ratio for the mass-yield curve of ≥18 was determined radiochemically by measuring the cumulative yields of ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ba}$ and ${}_{}{}^{127}{}_{}{}^{}\mathrm{Sb}$.