The neutrons produced by deuteron bombardment of a thin, enriched ${\mathrm{B}}^{11}$ target have been studied for nine different deuteron energies ranging from 1.60 to 2.70 MeV. The absolute differential cross sections for the production of neutrons feeding well-established states in ${\mathrm{C}}^{12}$ were determined. In addition to the monoenergetic neutron groups feeding the states of ${\mathrm{C}}^{12}$, previously unreported continuum neutrons due to many-body breakup of deuteron plus ${\mathrm{B}}^{11}$ system were observed and analyzed. The breakup mechanism is inferred to be a direct reaction process rather than the compound nucleus process. The angular distributions of neutrons leaving ${\mathrm{C}}^{12}$ in 15.11 MeV ($1^{+}$), $Q=-1.37\mathrm{} \mathrm{MeV} \mathrm{and} 12.73 \mathrm{MeV}$ ($1^{+}$), $Q=+1.00\mathrm{}$ MeV states were studied in detail. The effect of compound resonance at $E_d=2.18\mathrm{}$ MeV on the angular distributions of the above neutron groups was studied. The investigations were performed employing time-of-flight technique utilizing pre-acceleration pulsed, post-acceleration bunched deuteron beam from a 3-MeV Van de Graaff accelerator.

• Received 6 September 1962

DOI:https://doi.org/10.1103/PhysRev.129.1275