Discovery of /sup 260/Md and the decay properties of /sup 258/Fm, /sup 258m,g/Md, and /sup 259/Md [electronic resource].
- Livermore, Calif : Lawrence Livermore National Laboratory, 1985.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- Pages: 15 : digital, PDF file
- Additional Creators:
- Lawrence Livermore National Laboratory
United States. Department of Energy. Office of Scientific and Technical Information
- We have discovered a new neutron-rich isotope, /sup 260/Md, from /sup 18/O and /sup 22/Ne bombardments of /sup 254/Es. We observed a spontaneous-fission (SF) activity with a 32-day half-life in electromagnetically separated mass-260 fractions from these bombardments and we have measured the mass and kinetic energy distributions of this SF activity. The mass distribution was symmetric with the principal energy peak at 234-MeV total kinetic energy (TKE), similar to previous observations for heavy Fm isotopes. Surprisingly, we also observed a smaller symmetric component with 195-MeV TKE. We interpret these two peaks in the TKE distribution as arising from two types of fission in the same nucleus, or bimodal fission. The observed fission activity may be either from the SF decay of /sup 260/Md or /sup 260/Fm which would arise from electron capture (EC) decay of /sup 260/Md. We have eliminated the possible ..beta../sup -/ decay of /sup 260/Md by measuring ..beta../sup -/-SF time correlations for the decay of /sup 260/Md and we plan to determine if /sup 260/Md decays by EC by measuring time correlations between Fm x-rays and SF events. We also measured properties for heavy Fm and Md isotopes which include: (1) more accurate cross sections for the neutron-rich Md isotopes which we use to predict the production rates of yet undiscovered nuclides; (2) improved half-live measurements for /sup 258m,g/Md and /sup 259/Md; (3) confirmation of the EC decay of /sup 258m/Md by measuring Fm x-rays preceding the SF decay of /sup 258/Fm; and (4) very substantially improved mass and TKE distributions for the SF decay of /sup 258/Fm and /sup 259/Md.
- Published through SciTech Connect.
ACTINIDES '85, Aix-en-Provence, France, 1 Sep 1985.
Wild, J.F.; Hahn, R.L.; Henderson, C.M.; Dougan, R.J.; Lougheed, R.W.; Hulet, E.K.; Bethune, G.; Moody, K.J.; Dupzyk, R.J.; Suemmerer, K.
- Funding Information:
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