Energy Spectra and Angular Distribution of Photoneutrons from Carbon

Energy spectra and angular distribution of photoneutrons from carbon are studied by irradiation with a 30-Mev bremsstrahlung beam. The spectra exhibit a fine structure from which the following levels in C¹² may be distinguished: 21.4, 22.2, 22.9, 23.6, (24.3), 24.8, and 25.6 Mev. Many of these coincide with levels found in the C¹²(γ, p) and C¹²(γ, 3α) reactions.Photoneutron emission occurs predominantly by transition to the ground state of C¹¹.The angular distribution is of the form 1+1.5sin²θ for all neutrons having energy Eₙ>3 Mev. This distribution agrees with that expected according to Wilkinson's independent-particle model for ejection from the $l=1$ orbit.