γ-RAYS PRODUCED BY SLOW NEUTRON CAPTURE IN BERYLLIUM, CARBON, AND NITROGEN

The γ-rays produced by slow neutron capture in beryllium, carbon, and nitrogen have been investigated with a pair spectrometer. Only one γ-ray was observed to follow capture in beryllium and in carbon; nine were observed from nitrogen. The neutron binding energies computed from the energies of these radiations are: Be10, 6.797 ± 0.008 Mev.; C13, 4.948 ± 0.008 Mev.; N15, 10.823 ± 0.012 Mev. The nitrogen γ-rays can be fitted into a term scheme containing the previously known excited states of N15, obtained from the study of (d, p) reactions, together with one excited state at 9.16 Mev., hitherto unreported. A comparison of the intensities of the nitrogen and beryllium radiations shows that the radiative capture cross section of nitrogen is at most 160 millibarns.