Measurement of delayed-neutron yield from 237Np fission induced by thermal neutrons

The delayed-neutron yield from thermal-neutron-induced fission of the 237Np nucleus was measured using a sample periodically exposed to a pulsed neutron beam with subsequent detection of neutrons during the time intervals between pulses. The experiment was realized on an Isomer-M setup mounted in the IBR-2 pulsed reactor channel equipped with a mirror neutron guide. The setup and the experimental procedure are described, the background sources are thoroughly analyzed, and the experimental data are presented. The total delayed-neutron yield from 237Np fission induced by thermal neutrons is ν d = 0.0110 ± 0.0009. This study was performed at the Frank Laboratory of Neutron Physics (JINR, Dubna).