GAMMA-RAY WIDTHS IN C13, LI6, AND P31

The width of the 3.68-MeV level of C13 has been measured and found to be =0.440.04 eV. After correction for the E3 dependence, this is 0.59 times as strong as the mirror transition in N13, in agreement with Morpurgo's prediction of approximate equality for M1, T=0 transitions in mirror nuclei. The C13 width was obtained from a comparison of the resonant scattering of bremsstrahlung by C13 with that by the 3.51-MeV level of P31 and the 3.56-MeV level of Li6. The widths of the P31 and Li6 levels were measured in self-absorption experiments, and found to be 528 meV and 8.10.5 eV, respectively. A limit on the energetically allowed but spin- and parity-forbidden decay of the Li6 level to +d was established as d<1.3 eV. © 1969 The American Physical Society.