Total thermal radiative neutron cross sections have been measured on natural and enriched isotopic targets containing ${}^{6,7}\mathrm{Li},{}^9\mathrm{Be},{}^{10,11}\mathrm{B},{}^{12,13}\mathrm{C}$, and ${}^{14,15}\mathrm{N}$ with neutron beams from the Budapest Reactor. Complete neutron capture $\gamma$-ray decay schemes were measured for each isotope. Absolute transition probabilities have been determined by a least-squares fit of the transition intensities, corrected for internal conversion, to the $\left(n,\gamma \right)$ decay schemes. The $\gamma$-ray cross sections were standardized using stoichiometric compounds containing both the isotope of interest and another element whose $\gamma$-ray cross sections are well known. Total cross sections ${\sigma }_0$ were then determined for each isotope from the $\gamma$-ray cross sections and transition probabilities. For the ${}^{11}\mathrm{B}\left(n,\gamma \right){}^{12}\mathrm{B}$ reaction decay transition probabilities were determined for the $\gamma$ rays from ${}^{12}\mathrm{B}$ ($t_{1/2}=20.20$ ms) ${\beta }^{-}$ decay.

• Received 8 January 2016

DOI:https://doi.org/10.1103/PhysRevC.93.054306