Synthesis of element 108

Hassium is a synthetic element in the periodic table that has the symbol Hs and atomic number 108.

“…Thus the spontaneously fissioning activity observed is associated with the formation of the isotope ²⁶⁴108 in the reactions ²⁰⁸Pb(⁵⁸Fe, 2n) and ²⁰⁷Pb(⁵⁸Fe, n). The time distribution of spontaneous fission fragment tracks in the reactions ^207,208Pb + ⁵⁸Fe does not differ from that observed in the reaction ²⁰⁸Pb + ⁵⁴Cr.

Bearing in mind that the expected α-decay half-life of the isotope ²⁶⁴108 (Ref. 6) is smaller than the value measured by detecting spontaneous fission we arrive at the rather essential conclusion that the even-even isotope ²⁶⁴108 undergoes mainly α-decay followed by the formation of the daughter α-emitter ²⁶⁰106 and the spontaneously fissioning granddaughter nuclide ²⁵⁶104, i.e.
                α                   α
²⁶⁴108 —> ²⁶⁰106 —> ²⁵⁶104(SF).
This indicates that in the given decay chain the stability of nuclei with Z=106, 108 against spontaneous fission turns out to be comparable to (or possibly even higher than) that of the nucleus ²⁵⁶104.

From “On the Stability of the Nuclei of Element 108 with A = 263-265” Yu.Ts. Oganessian, A.G. Demin, M. Hussonnois, S.P.Tretyakova, Yu.P. Kharitonov, V.K. Utyonkov, I.V. Shirokovsky, O. Constantinescu, H. Bruchertseifer, Yu.S. Korotkin. Zs.Physik A319(1984)215-217
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“Experimental Studies of the Formation and Radioactive Decay of Isotopes with Z=104-109” Yu.Ts.Oganessian, M.Hussonnois, A.G.Demin, Yu.P.Kharitonov, H.Bruchertseifer, O.Constantinescu, Yu.S.Korotkin, S.P.Tretyakova, V.K.Utyonkov, I.V.Shirokovsky and J.Estevez, JINR E2-84-651 (1984), p.4-7
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