Angular distribution of γ radiation following C 12(p 1, p 2 γ)C 12

Abstract

An analysis is made of the angular distributions of the 4.43-MeV γ radiation following C 12(p 1, p 2 γ)C 12 in the vicinity of the two resonance peaks at bombarding energies 5.36 MeV and 5.89 MeV. It is shown that the angular distributions of this γ radiation are strongly dominated not only by the two resonance levels ( 3 2 + and 5 2 +) in N 13, with excitation energies 6.91 MeV and 7.42 MeV (called C and E respectively), but also by another lower level ( 5 2 +) with 6.38 MeV excitation (called A) and their interference. A better fit between the theory and experimental data is obtained for reduced-width amplitude ratios γ′ s′ 1 l′ 1 γ′ s′ 2 l′ 2 γ s 1 l 1 γ s 2 l 2 = −2.3 and γ″ s″ 1 l″ 1 γ″ s″ 2 l″ 2 / γ s 1 l 1 γ s 2 l 2 = −0.32, where no prime, one prime and two primes are used for the levels C, A and E, respectively, and subscripts 1 and 2 for incoming and outgoing channels, respectively. The relationship N 2+ N 4 = N 0 is deduced, if the angular distribution is expressed by W( θ) ∝ N 0+ N 2 cos 2 θ + N 4 cos 4 θ. Finally, the effects of other neighbouring levels in N 13 are considered.