Angular Distribution of 2.6-Mev Gamma Rays from the ReactionPb208(n, n′γ)Pb208

Abstract

Gamma rays produced through inelastic scattering by lead of a collimated beam of fast neutrons from a reactor have been detected with a NaI(Tl) crystal. The relative yield of 2.6-Mev $\gamma$ rays from ${\mathrm{Pb}}^{208}$ was measured as a function of the angle between the incident neutrons and outgoing $\gamma$ rays. Good agreement is obtained between the experimental angular distribution and a calculated distribution based on a statistical model, and using quantum numbers $3^{-}$ for the 2.6-Mev state in ${\mathrm{Pb}}^{208}$.