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The T z =+ 1 2 beta-delayed proton precursors 65Ge, 69Se, 73Kr and 77Sr have been identified and their decay energies, half-lives and proton branching ratios determined. The half-life of the previously unreported 77Sr is 9.0± 1.0 s.

The reaction 14C(18O,12Be)20Ne at E = 88.7 MeV has been used to measure the mass excess of 12Be, the value 25.05 ± 0.05 MeV being obtained. An excited state was also observed at 2.09 ± 0.05 MeV in 12Be.

The new T z = − 3 2 isotope, 45Cr, has been produced by the 32S(16O, 3n)45 Cr reaction. Its half-life was measured to be 50 ± 6 ms. A single β-delayed proton group with center-of-mass energy 2.10 ± 0.05 MeV was observed, corresponding to the decay of the lowest T z = 3 2 state in 45V.

The s + -decay of 49 Mn ( J π , T= 5 2 − , 1 2 ; t 1 2 =384 ± 17 ms ) has been observed; it exhibits a superallowed branch to its mirror, the 49 Cr ground state, and a (6.4 ± 2.6)% allowed branch to the 7 2 − state at 272 keV. The deduced Gamow-Teller matrix elements agree very well with shell model calculations that employ a modified Kuo-Brown interaction.

Beta-delayed protons, Elab > 1.2 MeV, were observed following the decay of 13O, τ 1 2 = 8.95±0.20 ms . Comparison of 13O decay-rates with those of the mirror nuclide 13B indicates a 15% deviation from mirror symmetry.

The introduction of spin exchange terms in the interaction is shown to reduce both (p,t) and (p, 3 He) cross sections. The S = 1 and S = 0 terms in the expression for (p, 3 He) still add incoherently but the relative strength of the former is reduced. Comparison with experiment shows satisfactory agreement.

Beta-delayed γ-rays have been observed from the decay of 72 Kr (τ 1 2 = 16.7 ± 0.6 s ) . A decay scheme is proposed based on γ-γ and β + -γ coincidence measurements. The total decay energy was measured to be Q EC = 5057 ± 135 keV. The value is compared with mass predictions.

Average radiation widths 〈Γ γ 〉 are calculated by a method that permits application to exotic nuclei where little spectroscopic information is available. The calculations are tested against 62 near-stable nuclei and - for the first time this has been possible - against 5 exotic nuclei for which 〈Γ γ 〉 has now been measured. Excellent results are obtained if level densities are calculated with the back-shifted Fermi gas model but not if Gilbert and Cameron densities are used.

In contradiction with a recent publication, we demonstrate that data on the β -decay of 145 Gd confirm in all respects the statistical conclusions derived in 1977 from a computer-simulated decay of the fictional nucleus, Pandemonium. Complex β -decay schemes based on singles spectra of β -delayed λ -rays must still be regarded as doubtful.

Experimental ƒt -values are used to examine various theoretical treatments of analogue symmetry breaking in superallowed Fermi β-decay. None of the fits to experiment in more than barely acceptable and, contrary to a previous analysis, we find no clear preference for one type of treatment over another.

The excitation energy of the lowest 0+ T = 2 state in 28Si was measured to be 15.206 ± 0.025 MeV. The state decays predominantly by isospin-forbidden α-particle emission. Its analogue in 28Al was also observed at 5.983 ± 0.025 MeV.

The first significant disagreement with recent “exact” shell-model calculations occurs in 17O(p, d)16O at Ep = 31 MeV. The 4+ level at 10.36 MeV has < 5% of its predicted intensity. Little 1p32 strength appears below 18 MeV excitation in agreement with the model.

Half-lives for 26 Al m , 34 Cl, 38 K m and 42 Sc are measured to be 6351 ± 10, 1534 ± 3, 929.2 ± 3.5 and 684.5 ± 1.2 ms, respectively. The results for 34 Cl and 38 K m are substantially lower than previously accepted values and tend to bring the ft -values into agreement with other superallowed decays. The mirror asymmetry for mass 34 becomes Δ = (−2.5 ± 1.7)%.

By consideration of the 28Si(t,p)30Si reaction, the sign of the interaction matrix element 〈d 3 2 2 ωVωs 1 2 2 〉 J=0 is determined to be negative, and the sign of 〈d 3 2 2 ωVωs 1 2 d 3 2 〉 J=2 to be positive. The method has quite general applications.

The anomalous behaviour of 35 Ar decay could be consistent with the suggestion of Salam and Strathdee that the Cabibbo angle vanishes at high magnetic fields.