ABSTRACT
The observation of beta-delayed alpha decay dates back to the first days of nuclear physics and the work of Rutherford on naturally occurring radioactive series. The characteristic onset of ß-delayed particle decay among exotic nuclei has often led to its being used as a means of identifying new nuclei. With a judicious choice of target, beam, and beam energy, it is not difficult to produce a single delayed-particle precursor, uniquely distinguished by its decay mode from all other activities produced simultaneously. Although, in principle, coincidence measurements between particles and γ-rays deexciting the daughter states can be used, the counting statistics are usually insufficient to permit application of the more sophisticated techniques: particle-X-ray coincidence technique (PXCT) and fluctuation analysis. Indeed, convincing tests of quenching calculations are difficult to perform since most direct ß-decay measurements suffer from a severe limitation: only a small fraction of the axial-vector strength gives rise to energetically allowed transitions.
