Decay modes of 250No

Abstract

The Fragment Mass Analyzer at the ATLAS facility has been used to unambiguously identify the mass number associated with different decay modes of the nobelium isotopes produced via 204Pb(48Ca,xn)(252-x)No reactions. Isotopically pure (>99.7%) 204Pb targets were used to reduce background from more favored reactions on heavier lead isotopes. Two spontaneous fission half-lives (t_1/2 = 3.7+1.1-0.8 us and 43+22-15 us) were deduced from a total of 158 fission events. Both decays originate from 250No rather than from neighboring isotopes as previously suggested. The longer activity most likely corresponds to a K-isomer in this nucleus. No conclusive evidence for an alpha branch was observed, resulting in upper limits of 2.1% for the shorter lifetime and 3.4% for the longer activity.

RevTex4, 10 pages, 5 figures, submitted to PRC

References in corpus (3)

• Nuclear Ground-State Masses and Deformations
• Fission barriers of neutron-rich and superheavy nuclei calculated with the ETFSI method
• Semiempirical Shell Model Masses with Magic Number Z = 126 for Superheavy Elements

Cited by in corpus (8)

• Fission properties for r-process nuclei
• Spontaneous fission half-lives of heavy and superheavy nuclei within a generalized liquid drop model
• Discovery of Isotopes of Elements with Z $\ge$ 100
• The competition between alpha decay and spontaneous fission in odd-even and odd-odd nuclei in the range 99 \leg Z \leg 129
• Stepping into the Sea of Instability: The New Sub-us Superheavy Nucleus 252Rf
• Study of the production and decay properties of neutron-deficient nobelium isotopes
• Production cross section and decay study of ${}^{243}$Es and ${}^{249}$Md
• Theoretical studies on structural properties and decay modes of ${}^{284-375}$119 isotopes