E2 AND M1 MATRIX ELEMENTS IN B10

γ-ray decay of the B10 2.15- and 3.59-MeV levels was studied following population via the B11(He3, α)B10 reaction at EHe3=2.6 MeV. The γ rays were detected in coincidence with α particles observed in an axially symmetric silicon detector centered at 180° to the beam. γ-ray branching ratios were extracted for both levels. From the angular distributions of the decay γ rays, results were obtained for the E2M1 mixing ratios x of the decay of the 2+ 3.59-MeV level to the 3+ ground state, the 1+ 0.72-MeV level, and the 1+ 2.15-MeV level, respectively, as follows: +0.31<x<+2.1, x-1=+(0.11±0.10), x=-(0.38±0.09), all pertaining to ΔT=0 transitions. For the decay of the 2.15-MeV level to the 0.72-MeV level, x=-(0.29±0.05)or-(3.39±0.55). Combining these results with previous work gives information on the magnitudes as well as the relative phases of the M1 and E2 matrix elements considered. These results are compared with the predictions of the independent-particle model. © 1968 The American Physical Society.