The measurements of gamma-spectra emitted in capture of thermal neutrons by 11B nuclei

The spectra of gamma rays emitted on radiative capture of thermal neutrons in Be, 11B and C are measured. The Be and C spectra have shown all the known transitions with energies above 1 MeV. These elements were used as a standard to determine absolute gamma-yield following the decay of the 12B compound state, where are observed only a direct transition to the ground state with a yield of 20±8 gamma quanta per 100 capture events. 9 refs.; 3 figs.; 1 tab