Insight into excitation energy and structure effects in fission from isotopic information in fission yields

Abstract

The use of the inverse kinematics technique and a magnetic spectrometer permits the simultaneous measurement of proton and neutron content of full fission fragment distributions. This paper reports new measurements of five fissioning systems---$^{238}\mathrm{U},\phantom{\rule{0.16em}{0ex}}^{239}\mathrm{Np},\phantom{\rule{0.16em}{0ex}}^{240}\mathrm{Pu},\phantom{\rule{0.16em}{0ex}}^{244}\mathrm{Cm}$, and $^{250}\mathrm{Cf}$---produced in inelastic scattering, transfer, and fusion reactions at different excitation energies. As a result, isotopic, elemental, and isotonic fission yields are presented. The contribution of the different fission modes and the proton even-odd effect are studied. Structure effects are investigated by means of the neutron excess and the total neutron multiplicity as a function of the fragment atomic number.