We have extended the experiment reported in Bradfield-Smith et al. ͓Phys. Rev. C 59, 3402 ͑1999͔͒ concerning the 18 Ne(␣,p) 21 Na reaction, which is of importance to nuclear astrophysics. This study covered an energy region ϳ1.7-2.9 MeV in the center of mass frame of the 18 Neϩ␣ system. A change in the detector geometry resulted in an increase in the detection efficiency and significantly reduced the proton background that hindered the previous measurement. A direct measurement of the energy loss of the 18 Ne beam, as it passed through He gas, was undertaken to reduce a major source of uncertainty in the determination of the stellar reaction rate. Eight states have been identified in the compound nucleus, 22 Mg. These resonances were used to calculate an enhanced stellar reaction rate which shows good agreement with theoretical predictions ͓Görres, Wiescher, and Thielemann, Phys. Rev. C 51, 392 ͑1995͔͒ at and above a temperature of 1.5 GK. The impact of this enhanced stellar reaction rate upon the nucleosynthesis that occurs during the peak phase of an x-ray burst has been investigated.

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An experiment was performed at the Australian National University to study the 9 Be( 6 Li, 6 Li) 9 Be * → α + α + n reaction. This experiment was designed to study the breakup of 9 Be, in an attempt to quantify the contribution played by the 5 He + α and 8 Be 2 + + n channels for the low lying excited states. This information is required in order to resolve uncertainties in the α + α + n → 9 Be reaction rate in high-energy and neutron-rich astrophysical environments such as supernovae. Angular correlation measurements have been used to deduce that the 2.429 MeV state breaks up almost exclusively via the 8 Be 2 + channel. This method of identifying the break-up channel resolves the problem of distinguishing between the 8 Be 2 + and 5 He g.s. channels which are kinetically identical at this excitation energy.

An experiment was performed to study the 9 Be( 6 Li, 6 Li) 9 Be * → α + α + n reaction. This experiment was designed to study the breakup of 9 Be in an attempt to quantify the breakup yield for each of the decay channels (n + 8 Be g.s , n + 8 Be 2 + , and α + 5 He g.s ) from the low-lying states. The results suggest that the population of states in 9 Be from 1.68 to 11.28 MeV can be identified. Branching ratios for each of the breakup channels have been estimated for these states. These results are compared with earlier experiments and with theoretical predictions. They confirm the theoretical claim that the n + 8 Be 2 + and α + 5 He g.s channels increase in importance at higher excitation energies.

Evidence has been found for a broad unbound state near 1 MeV excitation in 9 B that is a candidate for the long-disputed 1 2 + mirror of the unbound 1.68 MeV state in 9 Be. Reactions of 6 Li+ 6 Li were studied with a 60 MeV beam incident on a 240 μg/cm 2 6 LiF target. The breakup fragments from the decay of the reaction products were detected in five Si-Si-CsI telescope detectors and the breakup particles were reconstructed using the technique of resonant particle spectroscopy. It is shown that contrary to a previous study, the