Neutrons and photons with energies from 100 MeV to 1.3 GeV are registered in a cluster of seven hexagonal BaF 2 scintillator modules. The neutron-induced hadronic shower is studied as a function of the incident neutron energy and is compared with the photon-induced electromagnetic shower. From the neutron flux and spectral distribution at the position of the BaF 2 detector, which were measured with a calibrated liquid scintillation detector, the absolute efficiency for neutron detection is determined as a function of the incident energy. A simple exponential relation is used to extrapolate to zero electronic threshold. The results are compared with GEANT3 simulations.