First observation of the nuclei87Tc and88Tc

Abstract
The gamma decay of excited states in the neutron deficient isotopes 87Tc and 88Tc has been observed for the first time. The fusion-evaporation reaction 58Ni(32S, p2n)87Tc and 58Ni(32S, pn)88Tc at 110 MeV, 40Ca(50Cr, p2n)87Tc and 40Ca(50Cr, pn)88Tc at 170 MeV and 58Ni(36Ar, alpha pn)88Tc at 145 MeV beam energy were used. Unambiguous identification of these nuclei which are populated with less than 1 mb cross section was achieved with coincidences between the gamma radiation and the evaporation residues detected in a recoil mass separator. From gamma gamma coincidence data, a decay scheme of 11 transitions was constructed for 88Tc, the ground state of which is suggested to have Ipi =7- or 8+. Two transitions identified in 87Tc follow the pattern of a g9/2 one-quasiparticle band.

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