Neutrons from Deuteron Bombardment of Boron

Abstract

A natural boron target has been bombarded by 920 keV deuterons, and the emitted neutrons detected using nuclear emulsions. A new procedure for analysing measurements is described ; this procedure allows approximate corrections for errors in geometry in the plane of the emulsions. The dependence of resolution on various experimental factors has been studied, and the resolution achieved is indiCated by peak widths of 245 ± 25keV and 360 ± 50 keV at neutron energies of 9·7 MeV and 13·9 MeV respectively. The angular distributions of the neutrons from the 10B(d,n)l1C reaction corresponding to the ground state of 11C, and the neutrons from the 11B(d,n)12C reaction corresponding to the 7·66 Me V state in 12C, have been determined; both distributions may be attributed to compound nucleus formation. A search has been made for a neutron group corresponding to an excited state at about 5·5 MeV in 12C suggested by Glassgold and Galonsky (1956) on the basis of the a-particle model. An upper limit for the intensity of any such group is set at 1 per cent. of the intensity of the group corresponding to the first excited state in 12C.