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For many nuclei beyond the proton drip line in the Z > 72, N > 82 region, both proton and α emission are energetically allowed. In the case of some proton emitters, there are α-decay chains emanating from both parent and daughter nuclei. This means that if the mass excess of one member of an α-decay chain is known, then the mass excesses for all members of both chains can be obtained. In addition, proton separation energies may be derived for nuclei in the α-decay chain of the proton emitter. The method of time- and space-correlations also allows the identification of isomeric states in these nuclei. As an example, a large number of mass excesses and proton separation energies for ground and metastable states have been derived from Q α and Q p values obtained from the proton emitters 165,166,167Ir, 171Au, 177Tl and their daughters.

The α decay of 186Bi was investigated via the 97Mo(92Mo, p2n) reaction and the use of a fragment mass analyzer with a double-sided Si strip detector. In contrast to an earlier work wherein only one α transition was reported, we observed two transitions arising from two isomers in 186Bi with energies and half-lives of: 7158(20) keV, T1/2 = 15.0(17) ms; and 7261(20) keV, T1/2 = 9.8(13) ms.

Fine structure in theα decay of192Po has been observed leading to the identification of an excited 0+ state in188Pb at 571 (31) keV. The half-life of192Po has been determined precisely to be 33.2 (14) ms and theα-branching ratio of the daughter188Pb has been deduced to be 0.085 (13).