DOUBLE-DIFFERENTIAL BERYLLIUM NEUTRON CROSS-SECTIONS AT INCIDENT NEUTRON ENERGIES OF 5.9, 10.1, AND 14.2 MEV

Beryllium neutron-production cross sections have been measured using the time-of-flight technique at incident neutron energies of 5. 9, 10. 1, and 14. 2 MeV, and at laboratory angles of 25, 27. 5, 30, 35, 45, 60, 80, 100, 110, 125, and 145 deg. The differential elastic and inelastic cross sections are presented. Inelastic reactions are defined as those reactions that proceed through the states at 1. 69-, 2. 43-, 2. 8-, and 3. 06-MeV excitation energy in **9Be. Comparison of the emission energy spectra with calculations using the ENDF/B-IV beryllium cross sections shows that the ENDF/B cross sections strongly overemphasize the low-lying states in **9Be. These results are relevant to fusion reactors.