Leigh Harwood

Comparison of alpha spectroscopic factors on /sup 24,26/Mg:(/sup 14/N,/sup 10/B) reaction

Cross sections for states populated in the /sup 24/Mg(/sup 14/N,/sup 10/B)/sup 28/Si and /sup 26/Mg(/sup 14/N,/sup 10/B)/sup 30/Si reactions at 83 MeV were measured. Equal strengths for population of /sup 28/Si and /sup 30/Si ground states were observed, in contrast to (/sup 16/O,/sup 12/C) and (/sup 12/C,/sup 8/Be) reactions, but in agreement with (/sup 6/Li, d) results and with theoretical predictions.

Cluster nature and parity of the 9. 155 MeV state in /sup 15/N

The lifetime of the 9.155 MeV J = 5/2 state in /sup 15/N has been measured to be < 13 fsec from a study of the /sup 12/C(/sup 7/Li,..cap alpha gamma..)/sup 15/N reaction at E/sub 7Li/ = 28 MeV. The ..gamma.. decay from the 9.155 MeV state to the 5.30 MeV 1/2/sup +/ state is established as E2 and thereby determines the parity of the 9.155 MeV state to be positive. Particle-gated ..gamma..-ray spectra from /sup 12/C(/sup 7/Li,..cap alpha gamma..) and /sup 12/C(/sup 6/Li,/sup 3/He..gamma..) reactions show that the 9.155 MeV state has a large triton cluster parentage. The other member of the unresolved doublet, the 9.152 MeV 3/2/sup -/ state, has a very small cluster parentage. These results are in disagreement with simple /sup 12/C + t interpretations of /sup 15/N but agree with weak coupling model calculations.