The (n, 2n) cross section of 9Be in the energy region 2.0–6.4 MeV

Abstract

The (n, 2n) cross section of 9Be was measured in the energy region 2.0–6.4 MeV and with an accuracy of about 8% above 3.2 MeV. The two neutrons in the (n, 2n) reaction were detected by a large liquid scintillator by measuring the correlation time between the pulses due to the two neutrons. The (n, 2n) cross section increases rapidly above the threshold at 2.70 MeV for the inelastic neutron scattering to the 2.43 MeV level of 9Be, which subsequently decays by neutron emission. There also exists a small (n, 2n) cross section in the energy range 2.0–2.7 MeV.