High efficiency neutron spectrometer with low background

A neutron energy spectrometer with a geometry close to 4π solid angle operated in the (1-5) MeV energy range at a suitable for a cold fusion experiment configuration and a very good n/γ discrimination, has been constructed. Tests of registration efficiency, energy resolution and radiation type identification have been made with a help of low intensity neutron and gamma sources. The spectrometer has shown the efficiency of about 10% at the 2x10-3s-1 background level and permits one to measure a neutron energy spectrum at a very low intensity of the source. Physical principles, design of the neutron detector system and results of its testing are described. 6 refs.; 6 figs.; 1 tab