EXCITED STATES OF 11C FROM n–γ ANGULAR CORRELATK AND GAMMA BRANCHING RATIOS

Abstract

An experimental study of excited states of 11C below 6.5 MeV has been made using the 10B (d, nγ)11C reaction at a deuteron bombarding energy of 0.8 MeV. Measurements were made of the n–γ angular correlations of the ground-state gamma transitions from the 6.49- and 4.32-MeV levels, and of the gamma-ray branching ratios from the 6.49-, 4.81-, and 4.32-MeV levels.Theoretical analysis of the n–γ angular correlations suggests that the J values of the 6.49- and 4.32-MeV levels are (3/2), (5/2), or (7/2). The parities of all the states observed in this experiment are already known to be negative from high-energy stripping data. A comparison of the experimental branching ratios with theoretical branching ratios predicted by the intermediate coupling shell model is consistent with the following spin and parity assignments in 11C: ground state (3/2)−, 2.00 MeV (1/2)−, 4.32 MeV (5/2)−, 4.81 MeV (3/2)−, and 6.49 MeV (7/2)−.